I wasn't referring to "whitewashing" situations--but I agree with Christopher's point in that regard.There's massive shade thrown to actors who take "whitewashed" roles or is that not what you mean?
I was referring specifically to "fan boys" who attack non-white actors and women nearly every time they get cast in a role--sometimes even when that role does not have a previously specified skin color attached to it (as in The Last Jedi or this Starfire).