Maybe it's "grander" than simply being snached from your home and put on slave ships or being captured by other black people and sold into slavery.
Africa as it stands with its poverty/war/corruption (not every inch of africa is some hellhole)... might not be something that some want to be associated with.
But American enslavement of black/african people is relatively recent. Its not like - for lack of another example coming to mind - ancient Egypt. Where people have to make a lot of assumptions.
Also it gives some people something to hold on to and feel like they are superior to white people. Coz god didnt just abandon them it was "prophecy that had to be fulfilled" so white people arent better than us coz black people are the original/real humans. And white people are mutations/aliens who stole the planet and black peoples birthright...
I dont know the motivations for this,I can only guess.
History is important, but i feel black people worldwide should look onwards and upwards. For me my being just black/african is enough. But i cant discount other people "beliefs" and feelings/experiences.