> Not all black people are Africans or have African heritage. Far from it, in fact.

Exactly. That's the "rational" point: the mistake was training the data on anything but the target population. Nobody is contenting that it could have been trained on something else: it wasn't and that fact is the problem.

> Also: darker? Darker than what? Are you taking “white” as your baseline

Darker than the white people the algorithm turns most inputs into. Have you seen the results?