It is an undeniable fact that modern Americans benefitted from slavery and black Americans are still harmed by it.
In US counties today, a larger local slave population in the past was correlated with lower percentages of uninsured white people, higher white median incomes, lower white poverty rates, higher white homeownership rates, and lower percentages of white people on food stamps.
Slavery was an early driver of economic growth. The US simply would not be in the high economic position it is now and the African countries who were raised for their population would not be so comparatively impoverished.
The perpetrator of slavery was ultimately the American government who made it legalized, encouraged, and enforced it. As the current stewards of our government, we are all responsible for the harm done in the past and the harm still being done to our fellow Americans.