The cruelty and whippings happened but they're quite overstated in the received version of history. Slavery is, in itself, a form of degradation. My family and I are fortunate and blessed in that we can afford shelter, food, clothing, and medical care with what we earn from our work. Therefore, no, I wouldn't want to trade places with those slaves. However, I can't speak for the many laborers in our own times who work from sunrise to sundown or longer daily yet can't afford decent shelter and raiment, sufficient nutrition, and medical care; they might feel differently. So, too, those who can't find steady work at all, through no fault of their own.
Regardless, that's peripheral to the point of the post to which you responded and the point you yourself made. You asserted that slaves weren't compensated for their labor. True, they weren't paid in money. They were, as I pointed out, compensated by being given food, shelter, clothing, and medical care, which is more compensation that many laborers receive now. Again, this is not a justification for the slavery, nor does it excuse all that what wrong about the practice of it. It is, though, one of several reasons why reparations aren't justified.
Then why didn't the Africans? Skin color? That hasn't held back any of the Orientals or the Asian Indians. So there must be more to it than merely skin and a few physical features that differ from the White majority.