They are still dealing with the effects of social apartheid in their country.
Past a certain level of social class, blacks are almost invisible, be it economically, in governance or academia.
They did not have a civil rights revolution on the scale of the US, and furthermore I don't believe the 'black race' as it were has ever been truly galvanized. I think the 'one drop rule' in the US had the unintended effect of strengthening the black community. In countries like Brazil, you have people wanting to identify as anything but black - in fact, they have multiple different racial categorizations to describe themselves; black or preto being just one of them. They also have the visibly ethnically mixed group or pardo, which make up the sizable majority of the country. It should not be lost on anyone that majority of Brazilians have at least some African ancestry. It's the virulent Europeanization that has also led to the dissolution of strength of the black community in Brazil. They basically accepted immigrants from Europe to "whiten" the country, because the blacks outnumbered those of European descent at the turn of the 20th century. There are other factors obviously, but I feel these points are pivotal.