I wish my premise were completely false, but the fact that such a fuss was kicked up about Hermione Granger being cast black in The Cursed Child does demonstrate my point.

JK Rowling pointed out all of her non-white characters, but all we know about the rest are occasional hair and eye details. If a reader infers whiteness, then it is just that; an inference based on layers of prejudice and the fact that Rowling never bothered mentioning whiteness unless it was uncommon paleness.

Obviously that’s just one example, but what would you say Frodo Baggins’ skin colour was in Tolkien’s mind? Sherlock Holmes’ skin colour in Doyle’s? I don’t recall ever reading about either, but the racists would be up in arms if a Victorian Sherlock was cast black.