I mostly agree (bit of a theme here ;)), but I think you need to qualify that statement with “in America”. And even there, it is true only if you say “in America as a whole”. There are certainly times and places where it is quite possible for a Black person to be racist. I’m not convinced it’s always about power, though I suspect that in the USA it mostly is. To me, racism is a form of prejudice based (mostly) on skin colour. Though, of course, that could be my white privilege. I don’t see a difference between a white person saying I shouldn’t be married to my Black wife and a Black person saying the same thing. Both are wrong. Both are expressing a prejudice based on skin colour. Both are racist.