Why not do both?

> And while we're at it, why do US-based affirmative action programs not distinguish between descendants of slaves and recent immigrants from Africa

Slavery impacted affected West Africa as well. The trade eventually destroyed communities leaving them vulnerable to colonization and exploitation.

Some African countries have former slaves e.g. Liberia. Individual slaves were traded multiple times across different countries. Do you include slaves when America was a British colony or only after the revolutionary war.

I assume Affirmative action policies pertain to current racism not just past racism.