Sounds like your history textbook fell hard into what is commonly referred to as the Black Legend. Briefly, the Black Legend holds that colonization by Spain in the New World was disproportionately violent and devastating to Native Americas, especially when compared to the relatively benign and enlightened colonization attempts of the Dutch, French, and English. Accounts like Bartolomé de las Casas A Short Account of the Destruction of the Indies were reprinted for Dutch, English, and German readers and were widely circulated for, as you said, propaganda purposes and stirring up anti-Catholic sentiment.

Let's just be abundantly clear; colonialism is violent. There is no way to extract resources, labor, and territory from indigenous peoples without force. While Spain was forced to realize the many sins of colonialism early, and enacted the New Laws in 1542 to, among other things, protect indigenous populations from enslavement, rampant violence, territorial displacement, resource deprivation, and a multitude of forms of coercive, unpaid labor continued throughout the Spanish Empire for centuries.

Every colonial power needed to justify it's expansion into the New World. For nations like England, painting Spain as a disproportionately bloodthirsty and evil empire excused their own attempts to subjugate indigenous populations. They would save indigenous peoples' lives from the unique horrors awaiting them under Spanish control, as they save their souls with Protestant doctrine. The Black Legend was part of this justification. By portraying themselves as enlightened, and peaceful Protestant colonizers, English colonists excused centuries of violence throughout the eastern U.S., and justified their continual encroachment on indigenous territory.

In the United States we inherit a sanitized version of English settler colonialism. For example, English settlers established a precedent of total war against rival indigenous nations when they sought to exterminate the Pequot in the 1630s. The practice continued for centuries, and was adopted by the U.S. as accepted Indian Policy, as the new nation used the threat of genocidal violence to force agreement to unfair treaty after treaty as the nation spread ever westward. The role of the indigenous slave trade in the Southeast is practically forgotten in the popular consciousness. English slavers destabilized the region in the hunt for human property to sell to the Caribbean plantations. This slave trade practically depopulated the Florida peninsula by 1715, and very conservative estimates suggest 30,000-50,000 Amerindians were captured directly by the British, or by allied Native Americans for sale to the British, and enslaved before 1715. This number does not account for those who died in conflicts related to the slave trade, or died from the disease and malnutrition that followed refugees as they fled into the heart of the continent.

There was no benign colonial experience in the Americas. The entire premise of colonialism rests on violence, and successful colonial powers were willing to continually use force to achieve their own goals. Despite subsequent attempts to intentionally forget the centuries of enslavement, genocide, displacement, and the creation of an unhealthy world in the Americas, no whitewashing can hide the brutal impact of settler colonialism.

I am from the Philippines, which was both a colony of Spain for 300 years and the US for 50 years. We actually have examples of the "Black Legend" propaganda during the American period.

If the Spanish were as brutal as English-centric history books said, we would be just as white as Latin America is now. But we aren't. That's because the vast majority of the Native American deaths attributed to Spanish "brutality" were really just victims of the pandemics of European diseases. Even today, Latin America has far more surviving indigenous people than the United States or Canada.

Also notice the sheer difference in population makeup of Spanish-controlled areas of the Caribbean vs. non-Spanish controlled areas. The Dominican Republic and Cuba for example (both Spanish), have far less black ancestry than places like Haiti (French). Why? Because they had far less slaves.

Another comparison would be the population make-up of Brazil (Portuguese-held) vs. Peru (Spanish-held).

When it comes specifically to the Philippines, consider the following:

Unlike any other colonial power, the natives were considered true subjects of the crown (i.e. "citizens"). As long as you were Christianized, you were guaranteed basic human rights. Spain built infrastructure for the natives and encouraged education (free universal education was even implemented in the 1800s). It's why you can find old Spanish colonial architecture like roads or ports or churches even in remote towns in the Philippines (sadly, a lot of which were destroyed in WW2), in contrast to Indonesia or Malaysia or India, etc. where colonial architecture only existed in enclaves where the white people lived.

Mixed marriages were very common, and at times, encouraged. There was very little of the race-based colonial justification that was rampant in other colonial powers. In fact, most of the ruling aristocracy of the Spanish Philippines were natives (the Principalia), descendants of former chieftains and rulers.

Most of the struggles by natives during the Spanish colonial period were class-based and religion-based, rather than race-based. Though the Spanish did have the "limpieza de sangre" system, by which if you had a Muslim or Jewish ancestor within 5 generations you were considered "impure" (largely because of remaining Spanish animosity towards them after the Reconquista).

The Chinese were also regarded with suspicion, since one of the early governor-generals was assassinated by Chinese slaves. Though by the 1800s, most Chinese immigrants were fully Christianized and assimilated and into native society.

In the Philippines, slavery of Christianized natives was illegal via the New Laws (same as in Latin America). Though in the early period, the Spanish had a hard time eradicating the indigenous slavery system. Though colonial authorities did abuse natives through the encomienda system and later the polo y servicio (basically community service), they did not enslave anyone. Attempts at circumventing anti-slavery laws had harsh punishments. There were regular Royal Decrees aimed at decreasing such abuses.

Contrast that with the Dutch, Portuguese, and British holdings in the rest of Southeast Asia where their economy relied on slaves. Batavia had one of the largest slave markets in the colonial period, with direct links to the slaving networks of the Zanzibar Arabs. Many Christian Filipinos abducted by Muslim raiders and pirates were sold there (so many of them in fact that they became part of their own ethnic group later on - the Mardijker). The Spanish even filed a formal letter of complaint to the Dutch embassy in an effort to stop the traffic of abducted Filipinos. Spain also built watchtowers and defense fleets against raiders, even in non-economically important areas.

Spain pursued a doctrine of conversion and assimilation in their colonial possessions. Contrast that with other European powers who justified their colonialism with belief in racial supremacy and economic exploitation of slaves in plantations.

On one hand, it resulted in a far more complete destruction and replacement of native cultures with Spanish and Catholic culture (the Philippines today remains distinctly Hispanic in culture), but on the other hand, natives were regarded as human beings.

The contrast is most stark when you compare with what happened after the Philippines became a US colony (after the US defeated Spain in the Spanish-American War).

The Spanish called us "indios" (Indians) or "indigentas" (natives), but the Americans called us "ni--ers" (or at best, the achingly condescending "little brown brothers").

In US (and British) print media, Filipino natives were depicted as savages in leaf skirts with primitive spears and bone necklaces (google it). Like for real. There were very few accurate depictions of Filipinos. Americans even sought out the most remote tribes they could find and then brought them to the US to be displayed like zoo animals.

US Politicians justified the American colonization of the islands by claiming they were only doing it to "civilize" and "Christianize" Filipinos. Which is quite hilarious considering that virtually the entire Philippines was already Christian with a centralized government for more than 300 years by that time. None of that mattered. Americans took one look at our dark skin and pretty much decided we were savages.

So yeah, I'd actually argue that Spain was the KINDEST of the colonial powers. Not that that's saying a lot, of course. At the end of the day, they were still colonizers.