Originally Posted by
Fyraltari
That's also the case in Terry Pratchett's Discworld and that didn't stop him from having an entire book about humans being racist toward other humans.
Because racist people aren't prejudiced against people because they dislike specific shades of color, they're prejudiced against other people because they're part of a perceived out-group and they're using skin colour as a marker of that out-group. But the same person can hold prejudices against several different out-groups based on different criteria. For example, it's not uncommon for real-life white racist to hate both black people and white jews.