Persons who ask this question usually already have the answer in their minds. Saying that everyone who participated in and benefitted from slavery is culpable in it makes some people upset because it does not assign degrees of blame to various kinds of participation. Anyone carefully reading through the information at this site will be able to form his or her own opinion about this question. But here are some thoughts to ponder. Because in the Americas slavery was more closely linked to economic development than in the Africas, with slave labor at the base of agricultural and industrial development, the lasting benefit in the Americas has been much more visible than in the Africas.
African economies remain generally weak.
Viewed continentally, while some Africans benefitted by making and selling slaves, the American continent gained the labor that the African continent lost. In general, slaves in the Americas produced much more economic value than slaves in the Africas. That greater economic value had important lasting consequences for economic development in the Americas. Everyone who benefitted is to blame. Europeans who held slaves and lived in American economies generally benefitted more and in a more lasting way than Africans who held slaves or lived in African economies where slaves labored.