Who knows! Maybe all black people don't think the same way? Or maybe you should spend less time arguing with "activists" online. The internet isn't a great place to get to know the most rational people in any group.😅
But yes, as I said, I'm not arguing that there aren't plenty of racist Chinese people. And China's record on human rights is despicable. Anybody directly comparing China and America isn't a serious person. But again, if you think that "America is one of the most systematically anti-racist countries on the planet", I suggest that that's because you're not the target of any racism.
And gratitude doesn't seem like quite the right emotion for finally being treated as a full human being. Just FYI, it's probably blind spots like that that have people calling you names.