That's not how it works. Considering the amount of white characters vs black characters in fiction, black people, indian people, asian people, whatever skin color is not white would be hard pressed to cosplay as anything. Cosplay should be as inclusive as possible. It's a matter of responsibility and sensitivity. It's not about not being allowed to cosplay Pyke as a white person. It's about not representing yourself as black when you're not and not treating an ethnicity as a costume.
Lots of people still don't think blackface is that big a deal or that it's offensive. It's mostly because it doesn't affect YOU personally. Try to look at it from another perspective than yours, it's not that hard. Like, fuck would you slant your eyes if you cosplayed Bakugo or Ichigo? Come on.