Reality as we know it

White supremacism is the idea that Whiteness is a superior value. It’s slightly more benign version is that Whiteness is a default value. That if we do nothing to the stories, they will naturally end up White and that the only reason people of colour are showing up on screen is because of political meddling. There are other similar assumptions too, like the idea of the male default. No one will ask you why all the characters in your story are male. But if you write an all-female cast, people will ask why. This happens not because there is something weird about an all-female cast, but because long periods of exposure to stories with majority male characters have given many people the mistaken idea that there is something natural about those depictions - something real.