Fantasy and science fiction novels are metaphors for our world. If a speculative book looks at our world through the eyes of a marginalized person, white readers might not connect with that character, because they haven't faced racism. They're not excited by a plot where black and brown characters must fight white oppressors, because they have to see themselves as the villain rather than the hero. They see a main character that doesn't look like them, and without quite knowing why, they don't find the story relatable...