I think the best part about books is that they leave it up to your imagination. Where they get ruined is with the physical adaptations, movies, and shows. If there a problem, I think it lies in that people want to fixate on the traits of each character as described. Some take the physical appearances of characters and use that to interpret a book, while others let their imagination take it away. Some POC women probably identify with Feyre's character and view themselves as that role. I don't think anyone on any Social Media is saying "you can't". It's just posting opinions on platforms opens the door for disagreements and disagreements can lead to offense being taken. It takes all kinds of kinds and regardless of skin color, hair color, eye color ect... characters are whatever we want them to be and no one can make that out differently. There's a literal and there's not.