This is a total misreading of the situation. I'm not here to argue that the US has a perfect human rights record, but its an active topic of debate and reform are happening. Moreover, the idea that people are being incarcerated solely for their skin color is not "well documented" and strains credulity as a claim. If the claim is sentencing disparity, then sure there is an issue there, but your claim is wholly false.
Xinjiang is a completely different situation. We know factually that millions of people have gone through reeducation camps, the CCP is trying to eradicate the Uyghur language and force Han culture on the Uyghurs. You can see these modern day concentration camps from satellite imagery. There are well documented cases of forced sterilization. There is no legal process for appeals if a Uyghur is arrested, and we know many of the arrests are for religious practice. The world saw what the CCP did in Tibet, and we're seeing an even more grotesque version in Xinjiang.