Discrimination has nothing to do with being different. If you refuse to integrate into a society you move into, you're invasive. In asia, the cultures generally were violently opposed to anyone outside of their own due to valuing domination and didn't really care what race someone is. In Africa, the tribes had and have essentially a predatory view in which the strong prey on the weak and if one group or race is strong it should devour the weak, sometimes literally. In Arabia it was based around wealth enforced by violence but otherwise was very similar to the asiatic cultures' values. In Europe, it was essentially jockeying for hierarchy in prestige. In the Americas, all of them, the values were basically hardcore Darwinism.
There is no race, no group, no culture on Earth in which discrimination was about merely being or looking different. Ever. Such things were exclusively convenient identifiers of people who refused to integrate or which group someone belonged to.
I know he isn't from Earth, but the writers is and the writer is clearly writing about the real world with the fantasy setting as a vessel in this context.
The refusal of many people to accept that simple fact is why they so many problems regarding groups interacting with each other exists. Trying to force people to live together with radically different values just doesn't work, especially when at least one is clearly vastly more successful than the rest, yet you force it to treat the others as equally viable even though they are not. The result is purely a self-destructive erasure of anyone and any group that is not sufficiently violent and that society just gets more and more violent as a result.
They're barking up the wrong tree out of an idiotic, childish, imaginary worldview that they wish to be true with zero regard for what is actually true so that they can pat themselves on the back and brag about what "good" people they are to themselves.
