What do you think share cropping and Jim crow laws were? What do you think the several civil rights acts following the 14th amendment were addressing? What do you think separate but equal and then desegregation was? Why is it that there's always someone asking for "proof" of racism? Anyone with a high school diploma knows about these things and yet all of that well known history is insufficient proof.
edit: we rightfully so recognize people demanding proof of the holocaust as bad actors. why not with this?