Anglos deserve blame for about 3% of the demand side of African slaves. Africans deserve blame for literally 99% of the supply side of African slaves.
I believe that the American taxpayer is due reparations for paying for the care and feeding of democrat voters for a couple of generations.
If you really want to muddy the argument then bring up North African Piracy and the white slavery markets. America’s first foreign war was to put an end to that. Prior to that war New England churches had a special Sunday collection for a randsome fund to bail out merchant sailors captured in the Med.