like the guy said too complex.
But to some up, portuguese empire slave blacks for centuries, once they left, who was now in charged was brazilians white people descendents of portuguese, so they changed nothing actually, the only thing was now we were a free nation, but blacks in their view was still africans. So lands, money, politicians, were all white and making decisions in favor of whites.
Black excluded, found their "survival" going to big cities, creating favelas and trying to have humble jobs "like cleaning cars idk" and some in criminal life.
The black comuties was in fact only "looked by politicians" in beggning of the 90s, but with more effort in 21th century.