As a white woman I don't see much racism on fedi. Of course I don't, I'm clearly white. That's white privilege.
Yes I'm disabled, I'm a woman and am disadvantaged by that but those disadvantages would be magnified if I were also black.
Do I believe black people who say they experience racism here? Well why the hell wouldn't I? How does it benefit them to lie about it?
If I see racism that I recognise (and I'm not great at that but am trying to be better) I will report and block.