Expanding from an earlier answer of mine:

The image and idea of Columbus has gone through several phases, historically, but the focus here is going to be on the current epoch, and the rise of Columbus Day, as that plays the most important part in your question and the current perception and how we got there.

Columbus Day is very closely tied to Italian-American identity, originating almost exclusively as a holiday celebrated by Italian Immigrants, who wanted to celebrate their early ties to the 'New World', and stake their claim to being part of the idea of America (it is interesting to note, also, that Italian immigrant communities formed a unified idea of their Italianness in a way that wasn't quite as present in Italy itself although it quickly expanded to be more broadly embraced by immigrant Catholic communities generally in the period. This was a time when immigrants, especially Catholics and those from Southern Europe, were looked down upon and excluded by the many within the dominant White, Anglo-Saxon, Protestant culture of the United States - something I've written about previously specifically with an eye on the KKK in the 1910s-1920s, so may be of interest.

It expanded from Italian / Catholics communities into the wider American public over time and by the turn of the century was a somewhat popular celebration, having been designated a time for national celebration in 1892, and celebrating "American unity" in the words of one historian, as Columbus made for a great time to celebrate the 'melting pot' concept of which was becoming important to the mythos of the American identity

Angelo Noce, an Italian immigrant, was the big proponent of making it a Federal Holiday, with the stated goal of celebrating Italian Heritage through it, as they had been celebrating it for some decades before everyone else, and considered it "their" holiday. The Knights of Columbus were also a big supporter. Being predominantly Irish-Catholic, they likewise saw promise the elevation of a Catholic figure into the highest pantheon of American history, since, as noted, Catholic communities were likewise looked down upon, and seen as at best half American, with dual loyalties not only to their country, but the Pontiff in Rome.

Mass parades on Columbus Day quickly became a way for Catholic groups to demonstrate their civic pride and patriotism, and make the public spectacle of their Americanness. Kubal quotes one journalist who, writing about the parade and speeches given by Catholic organizations in in the 1890s, noted how "if any doubt existed in the minds of any that Catholics are Americans in every fiber of their being, it ought to vanish in the light of the addresses made everywhere yesterday".

Similarly, drives to put up Columbus statues were spearheaded by Italian-American fraternal groups such as the Columbian Federation or the Order of Sons of Italy in America (although as with the parades, some statues were pushed for by non-Italian Catholic groups). The statues were seen as important, visual symbols of their acceptance into American society, and also the growing ability for Italian-Americans to have political power. The very act of placing the statue in a public place by the government was an important reflection on what the Italian-American community was able to lobby for.

All of this lobbying and parading about saw real progress. In 1905, Colorado (Where Noce lived and had been strenuously pushing for this) became the first to recognize the day as an official holiday, dedicated as:

created for Catholics, particularly immigrant Catholics, and their children, the special Catholic holiday of the year [...] Christmas and Thanksgiving are religious or family holidays for all the people; Columbus Day belongs to our Catholic people.

Other states such as New York and California soon following suit. It would become a Federal Holiday in 1937, although by that point Noce had passed away so did not see his idea reach culmination.

And for the most part, there wasn't any of the controversy around him we now have. Regressive ideas about the indigenous peoples of the Americas, seen by far too many people as savage heathens for whom the introduction of Christianity and "Civilization" was a clear and important good for them (or at least the ones who survived the waves of genocide over the next few centuries...), Columbus and what he brought about was a clear and unambiguous positive for many. To quote one example given from the period:

Columbus was fired by the noblest motive that can guide the action of man. Every page of his life is teaming with evidence that he went forth on his perilous voyage to carry the Gospel to debased and erring savages, and to pass it to them with the torch of true Christian Civilization... Where shall we find a character worthy to be compared to with him? [...] Columbus was in a measure divine [....] Write his name beside no human hero.

Put plainly, that wouldn't have been to controversial in the 1890s when it was written. Columbus was a hero. He brought civilization to the virgin land of savages barely eking out an existence in the stone age, and made it a place where white people could put that land, which was being wasted by the backwards natives, to good use, and allow a great nation to flourish [ /s]. Italians, and Catholics, were pleased as punch to have this hero that they could point to as theirs, and stake their claim as being foundational to the American pageant.

Now, I need hardly point out that as time passed through the past century, attitudes changed significantly towards Columbus, and by the 1992 anniversary, Columbus was a very controversial figure, and has only gotten more so since then, as anyone looking at the news this week is clearly aware! Due to the 20 year rule, I'm not going to discuss the current stuff in-depth, and whether we should be destroying these statues but the indigenous peoples of the Americas are, unsurprisingly, the leader in opposition to the continuing celebration of a man who more and more are coming to recognize as the kickstarter of a mass genocide (and don't miss /u/Snapshot52 who covers the this angle here); and as perspectives change, the Italian-American lobby has been at the forefront of holding onto what they consider to be their national holiday.

McKevitt, Gerald. "Christopher Columbus as a Civic Saint: Angelo Noce and Italian American Assimilation." California History 71, no. 4 (1992): 516-33.

Timothy Kubal. Christopher Columbus and the Rewriting of the National Origin Myth. Palgrave Macmillan, 2008.

In addition to the answer provided by /u/Georgy_K_Zhukov, I wrote a Monday Methods piece awhile back that delves into some of the history behind Indigenous Peoples' Day--formally Columbus Day--and how this historical narrative fits into contemporary studies today. Here it is in full:

##Part 1

##Christopher Columbus and Columbus Day

Considering the above, I believe we have our answer. Is replacing Columbus Day with Indigenous Peoples Day revisionist? Answer: maybe. What historical record or account is being revised if we change the name of a recognized day? History books remain the same, with whatever book you pick up on any given day. Classroom curriculum remains the same unless note of this was already built into it or a special amendment is made. However, what has changed is the optics of the situation - how the public is perceiving the commemoration of Columbus and how they reflect on his actions of the past. Really, the change of the day reflects an already occurring change in society and societal structures. We are now delving into what our fellow flair and moderator, /u/commiespaceinvader, spoke about roughly a month ago: collective memory! Here are a few good excerpts (bold mine):

First, a distinction: Historians tend to distinguish between several levels here. The past, meaning the sum of all things that happened before now; history, the way we reconstruct things about the past and what stories we tell from this effort; and commemoration, which uses history in the form of narratives, symbols, and other singifiers to express something about us right now.

Commemoration is not solely about the history, it is about how history informs who we As Americans, Germans, French, Catholics, Protestants, Atheists and so on and so forth are and want to be. It stands at the intersection between history and identity and thus alwayWho s relates to contemporary debates because its goal is to tell a historic story about who we are and who we want to be. So when we talk about commemoration and practices of commemoration, we always talk about how history relates to the contemporary.

German historian Aleida Assmann expands upon this concept in her writing on cultural and collective memory: Collective memory is not like individual memory. Institutions, societies, etc. have no memory akin to the individual memory because they obviously lack any sort of biological or naturally arisen base for it. Instead institutions like a state, a nation, a society, a church or even a company create their own memory using signifiers, signs, texts, symbols, rites, practices, places and monuments. These creations are not like a fragmented individual memory but are done willfully, based on thought out choice, and also unlike individual memory not subject to subconscious change but rather told with a specific story in mind that is supposed to represent an essential part of the identity of the institution and to be passed on and generalized beyond its immediate historical context. It's intentional and constructed symbolically.

Thus, the recognition of Columbus by giving him a day that recognizes his accomplishments is a result of collective memory, for it symbolically frames his supposed discovery of the New World. So where is the issue? Surely we are all aware of the atrocities committed by and under Columbus. But if those atrocities are not being framed into the collective memory of this day, why do they matter?

Even though these symbols, these manifestations of history, purposely ignore historical context to achieve a certain meaning, this doesn't mean they are completely void of such context. And as noted, this collective memory forms and influences the collective identity of the communities consenting and approving of said symbols. This includes the historical context regardless if it is intended or not with the original symbol. This is because context, not necessarily of the all encompassing past, but of the contemporary meaning of when said symbols were recognized is carried with the symbol, a sort of meta-context, I would say.

For example, the development of Columbus Day, really the veneration of Columbus as a whole, has an interesting past. Thomas J. Schlereth (1992) reports this (bold mine):

In 1777, American poet Philip Freneau personified his country as "Columbia, America as sometimes so called from Columbus, the first discoverer." In 1846, shortly after the declaration of war with Mexico, Missouri senator Thomas Hart Benton told his Senate colleagues of "the grand idea of Columbus" who in "going west to Asia" provided America with her true course of empire, a predestined "American Road to India." In 1882, Thomas Cummings said to fellow members of the newly formed Knights of Columbus, "Under the inspiration of Him whose name we bear, and with the story of Columbus's life as exemplified in our beautiful ritual, we have the broadest kind of basis for patriotism and true love of country."^1

Christopher Columbus has proven to be a malleable and durable American symbol. He has been interpreted and reinterpreted as we have constructed and reconstructed our own national character. He was ignored in the colonial era: "The year 1692 passed without a single word or deed of recorded commemoration."^2 Americans first discovered the discoverer during their quest for independence and nationhood; successive generations molded Columbus into a multipurpose [American] hero, a national symbol to be used variously in the quest for a collective identity (p. 937).

For the last 500 years, the myth of Columbus has gone through several transformations, as the above cited text shows. While his exulting went silent for quite a while, the revival of his legacy happened at a time when Americans wanted to craft a more collective, national identity. This happened by linking the "discoveries" made by Columbus with one of the most influential ideologies ever birthed in the United States: expansionism, later known as Manifest Destiny. Schlereth (1992) further details this :

In the early republic, Americans began using Columbia as an eponym in their expanding geography. In 1791, for example, the Territory of Columbia, later the District of Columbia, was established as the permanent location of the federal government. A year later Capt. Robert Grant, in a ship named Columbia, made a territorial claim on a mighty western river (calling it the Columbia) for the United States in a region (later Oregon, Washington, Idaho) then disputed with the British. Britain eventually named its part of the contested terrain British Columbia. The ship Columbia in 1792 became the first American vessel to circumnavigate the globe, foreshadowing imperial voyages of a century later.

Use of the adjective Columbian became a commonplace shorthand by which one could declare public allegiance to the country's cultural pursuits and civic virtue. It was used in the titles of sixteen periodicals and eighteen books published in the United States between 1792 and 1825 -for example, The Columbian Arithmetician, A New System of Math by an American (1811).^9 Columbian school readers, spellers, and geographies abounded, as did scholarly, literary, and professional societies -for example, the Columbian Institute for the Promotion of the Arts and Sciences, which later evolved into the Smithsonian Institution.

It is this connection to expansionism that Americans identified with Columbus. This very same expansionism is what led to the genocides of American Indians and other Indigenous peoples of the Americas. I can sit here and provide quote after quote from American politicians, military officials, statesmen, scientists, professionals, and even the public about American sentiments toward Native Americans, but I believe we are well past that kind of nicety in this case. What we know is that expansion was on the minds of Americans for centuries and they identified The Doctrine of Discovery and the man who initiated the flood waves of Europeans coming to the Americas for the purpose of God, gold, and glory, AKA: colonization. Roxanne Dunbar-Ortiz (2014) makes comment by informing us how ingrained this link with Columbus is when 1798 hymn "Hail, Columbia" is played "whenever the vice president of the United States makes a public appearance, and Columbus Day is still a federal holiday despite Columbus never having set foot on the continent claimed by the United States" (p. 4).

To add a bit more to what's already been explained by /u/Georgy_K_Zhukov and /u/Snapshot52, it is worth stressing that American schools have a fair amount of responsibility for his prominence.

The American common school movement used a number of Protestant touchstones as it took shape in the mid-1800s. This included things like having boys and girls in class together, religious texts in early primers and readers, and routines and celebrations.

While some schools started off the day with prayers and religious songs, others moved into more secular celebrations of holidays, seasons, and Americana (a term that refers to songs, texts, ideas, and people associated with the United States. It includes things like Franklin an his key and the mnemonic ditty, "In fourteen-hundred ninety-two, Columbus sailed the ocean blue.") Early history textbooks would give lip service to the Indigenous people on this soil before colonizers arrived, but generally stated the timeline of America in 1492 and the arrival of Columbus and his ships. (That he didn't really land in the states and where he thought he was often deliberately left out of the narrative. A key feature of Americana is simple narratives and ideas that can be communicated easily to children.)

From an older response of mine:

Americana can best be thought of as the packaging of American history and touchstones for the next generation. It's a framework that led to the Washington and the cherry tree genre of stories, generations of school children memorizing the preamble to the Constitution, learning Christopher Columbus "discovered" American and mass dislocation and genocide of Indigenous people was simply "manifest destiny", and other broad strokes about what happened on this soil. This simplistic approach to American history was embedded in the texts children read and the way teachers talked about history. ... This meant that the 400th anniversary [of his landing] was everything. Schools across the country were planning celebrations, not because they coordinated, but because celebrations of events related to Americana was something you did in American schools.

In 1892, a poet to put to paper and created a special poem to commemorate Columbus' landing. His "pledge" was taken by children around the country and forever entwined the name of Columbus with this notion of America. In my response to the question, When did American schools start saying the pledge every day? I go into more depth about the relationship between Columbus and the pledge.

All of which is to say, Americana - as disseminated in American schools - stripped Columbus of his context, put him at the front of the list of Great American men, and let history and collective memory do the rest.

Not to deter new answers, but what /u/Georgy_K_Zhukov posted on the origins of Columbus Day should speak to your question.

As a follow-up question- though jailed and stripped of his position as governor, he was acquitted of his crimes by the Spanish crown despite the documentary evidence against him. How did Columbus manage to get off relatively scot free and even get funding for a fourth and final voyage? Crimes such as the mutilation of -Spanish- colonists seem like they would be fairly difficult for Ferdinand and Isabella to overlook.

A follow up: where can I read what those "long and well-documented list of brutal and tyrannical acts" were? In school they teach you he was an explorer in the age of discovery and little else.