When I was in Cacaxtla they show me this paintig, I believe this is very explanatory what is happening.
On left side there is a white guy and in the right side there is a black guy (the Black guy is the king 3Deer).
Look the legs of him, the darkest guy of the middle have the same leg.
The guy who guide me use this picture to explain me why and how Olmec-Xicalanca society racisms works. I think it is amazing. Maya/Olmec people indeed have the skin more darkner than Aztec or other North America tribes.