I think "shamed" is a bit of a loaded term, and a bit unclear. If you're asking about the differing legacies of the two systems, then I can shed a little light.

First, I'll go ahead and cite my sources.

1. If you're interested in a case study/microhistory of Brazilian slavery, I can't recommend "Dutra's World" by Zephyr Frank highly enough. It's an account of a Brazilian slave turned slave owner, and his complex place in Brazilian society in the first half of the 19th century.

2. For an American comparison, I have two books to recommend. "Slaves Without Masters" by Ira Berlin is, despite its age, a really solid look at the divides between Southern whites and free blacks in the antebellum period.

3. A more recent work that looks at antebellum race relations through the lens of color (as opposed to race) is "The Color Factor" by Howard Bodenhorn.

In a single word, the difference between the United States and Brazil (in terms of race and slavery) is fluidity.

Race in 19th century America was, for the most part, binary. You were either white or colored. On the census, people were either white, black, or mulatto, but that distinction was rarely seen outside of demographic data.

In Latin America, racial constructs were more nuanced. In addition to people who were "purely" European, African, or Native, there were multiple pardo/mixed-race groups.

I'll quote a couple of paragraphs from a paper I wrote in grad school, comparing and contrasting American and Brazilian slavery systems:

In mid-nineteenth century Brazil, the institution of slavery allowed the middling class of landowners to advance socially, as slaves were the most equally distributed asset in Brazil. Although the urban slave population was growing rapidly, so too was the population of free people of color. Antonio Dutra likely endured the Middle Passage some time in the 1810s, and was one of approximately 40,000 slaves in Rio at the time. Urban labor forces were highly service-oriented, for both slave and free populations. Brazilians imagined racial categories as a spectrum, rather than the sharply defined dichotomy created by Americans; thus, people of mixed race created much less disruption to existing social and political structures in Brazil.

In Brazil, the middling classes frequently rented domestic slaves by the month. This was an unheard of arrangement in the American South, where the distribution of slaveholders was much less evenly distributed. In nineteenth century Brazil, the population of free people of color rose steadily. Despite their ability to own property, they were discriminated against and relegated to certain occupations, such as barbering. Barbering was also an occupation for free men of color in the United States, an interesting parallel between the two societies. Dutra, like other middling wealth holders, were much more likely to invest in slaves than in land or real estate, due to the expense of the market.

This is a major difference from the American South. Alabamians in the 1830s and 1840s were far more likely to grow their wealth by purchasing land. Grants from the General Land Office were relatively inexpensive, and could be sold for a tidy profit after only a few years. Conversely, slaves were no longer being imported and were significantly more expensive to purchase and keep healthy and complacent. These concerns were present in Rio as well, but despite this, the slave economy was still a more profitable opportunity than the real estate market. This is the major difference between Dutra and Perteet. Dutra, a freed slave, held over half of his assets in human chattel. Just over one-third of his assets were held in real estate, and he had almost nothing in hard currency or notes. Perteet, free-born and raised by his wealthy white mother, held most of his fortune in real estate and precious metals.

*Solomon Perteet was the subject of my master's thesis. He was a free-born black slaveowner in Tuscaloosa, AL.

I hope my answer can give you at least a little bit of insight. I know it's not exactly what you asked, but I'm typing this on my phone and drinking red wine. I'd be happy to clarify or elaborate if you have any further questions.

I'll write this on the perspective of an economist who studies and researches brazilian economic history, therefore while it's not my field of specialty, I study under specialists and have studied the institution of slavery in Brazil.

First, while similar, the instutions of united states slavery and brazilian slavery have some very significant differences which will play a major part in OP's question:

As per FRAGOSO, João and FLORENTINO, Manolo on "O arcaísmo como projeto. Mercado atlântico, sociedade agrária e elite mercantil no Rio de Janeiro, c.1790-c.1840", slaves were seem fundamentally different in both societies due , mostly to, different theological justifications by catholics and protestants to slavery. In the US the slave was seem as an asset, akin to cattle and the institution of "slave reproduction" was acceptable, therefore labour was reproduced through time, yet in Brazil slaves were seem as a "reserve of labour" to be expended and destroyed itself on the process and the reproduction of said labour depended mostly on further trade. The ramification of this is quite noticeable on the stock of slaves in both societies upon the banning of the slave trade, with the US stock and prices being a lot more stable than the brazilian ones. This black market of ilegal slavers thrived so much and brazilian society largely ignored the ruling to such extent that even today there's a folk expression "Pra inglês ver", which roughly translates to "Only for British eyes" in reference to the defiance of the Aberdeen Act of August, 8 of 1845.

This is important due to the fact that in general, brazilian slaves were seem more as inhuman which reflected both on their conditions but also on their literacy rate as per "COSTA E SILVA, Alberto da on A manilha e o libambo. A África e a escravidão, de 1500 a 1700". This literacy rate also is a reflection of religious differences in both countries, as in the process of converting slaves protestantism expected literacy on it's practicioners, while catholic lithurgy was still performed in latim and had no such pressure on teaching it's practicioner how to write.

This phenomenon gives a very strong survivor's bias on historical accounts of brazilian slaves, as there are almost none, if at all first-hand accounts of slaves that hadn't ascended socially and economically and also, after emancipation, there was no significant socio-economic mobility to form a black middle-class in Brazil, in stark contrast with the US. Therefore, in Brazil the critical understanding of the institution of slavery was done mostly at it's early republic by sociologists and historians with some conciliatory notions such as "racial democracy" in which the mixing of races garanteed the eventual extiction of racism and the racial harmony in Brazil, a sentiment expressed clearly on João Batista Lacerda speech, the brazilian National Museum director and only latin american on the First Universal Congress of Race held in 1911 in London: (rough translation):

"In Brazil it has been observed that third generation mixed race sons have all the physical characteristics of the white race [...] some retain a few traces of their black ascendency due to influence of atavism [...] but the influence of sexual selection[...] tends to neutralize said atavism and remove all traces of the black races on the mixed race sons[...] Through virtue of this process of ethnical selection, it's only logical to expect that in the course of a century, mixed race will have disappeared on Brazil. This will coincide with the extinction of the black race amongst ourselves."

There theories gained wide acceptance in Brazilian culture and reflect even today in our consciousness, being subject of state propaganda by both our dictatorial governments. The critique of said theories being an ongoing process with newer sociologists and historians such as Florestan Fernandes, Milton Santos and so on, accusing the classical studies like Gilberto Freyre's "Casa Grande e Senzala" as whitewashing and dated. This countermovement has only gained steam on our wider culture in the last 30 to 20 years and still is an ongoing critique.

EDIT: Formatting

I think the answer to your question is complicated because the simple answer is that it is "shamed". The real question, I think, is: Why is there this perception that Brazil is less racist than the United Stated?

But before trying to answer this question, I've noticed that some answers here pointed that race in Brazil is more fluid than in the US and that miscegenation was a lot more common. And while that is true, it should be noted that in the late 19th century there was an oficial government policy that tried to "whiten the race" that was supported by an widespread eugenics ideology. To do so, they encouraged the immigration of Italians and Germans to come work in the coffee farms and in the early fabric industry. As I commented in another answer, the painting A Redenção de Cam, in which a black grandmother is depicted praising the fact that her grandchild was born white, perfectly shows this ideology. Being black was clearly seeing as something undesirable, which had real very economical consequences. Like Carlos Hasenbalg and Suellen Huntington wrote in this article: "This labor market preference for whites first, mulattoes second, and blacks last created a status and income continuum corresponding to the color continuum, in contrast to caste-color line created in the United States."

Nowadays in Brazil we frequently talk about the "Myth of Racial Democracy in Brazil", an idea that has it's roots in Gilberto Freyre's works (which is the reason why someone pointed that Freyre is considered borderline racist) and that became more prominent during Getúlio Vargas's years as president (1930-1945). Vargas tried to sell this vision of Brazil as an exotic paradise where all races lived together in harmony. While that vision was absolutely untrue, it became part of Brazil's imaginary and for a long time it was believed (even in academical circles) that all our issues came from economical inequity and that once that was fixed everything else would follow suit. The problem with that believe is that for most of our history we simply ignored the many ways in which slavery and racism affected and still affects black people in Brazil. For exemple, according to the 2017 Atlas de Violência 71 of every 100 people murdered in Brazil are black. Also, according to a study conducted by IPEA in 2015, of the total population who can't read or write 9,160,111 are black, while that number drops to 3,610,529 amongst the white population.

There are several studies that tackle this issue in depth. Amongst them, I would like to recommend SCHWARCZ, Lilia Moritz. Questão racial e etnicidade. In: O que ler na ciência Social brasileira (1970-1995)[S.l: s.n.], 1999. in which the author analises how the understanding of racial and ethnical issues in Brazil have changed during the 20th century and what were the powers at play in those changes.