Not long before Europeans appeared in Congo basin, most of the local natives of area were robbed of their lands by new arrivals of taller black people. Their co-existence with these new masters is nothing less than slavery even in modern times. I wonder... how deep is that box of Pandora, that you want to open? Are you ready to pay for sins of your ancestors or is this exclusive thing to Whites only? Are you even aware, that significant part of Europeans in US initially were brought to US as slaves?
Europeans did not brought slavery to Africa and neither to US, where locals were happily enslaving each other. 500 years ago before arrival of Europeans with rare exceptions, any society in Africa had slavery. History is unpleasant, but that has hardly anything to do with ongoing war, that has reached heat in modern US. Btw, Hitler also eradicated Jews with the exactly same ideas about Aryan race, but you might need to get past 500 years in your history book to realize that.