What do they hold as superior? Now that Nida could talk about. He simply raises an arm and rolls up a sleeve to bare more skin. This. It's stupid, but it was a thing that happened.

"Ethnicity. Skin tone, because it marks you as from one region or another. Or being born within the limitations of a city state. And, of course, magic. Our world has a sort of natural user of magic called a Sorceress. They tend to go crazy, have a ton of power, and think it is their right to rule. Oh, and you have the military dictatorships like Galbadia, the Deling family has ruled there as 'Presidents' for a while and they like military conquest. My home was annexed and rebellions were frowned upon. So plenty of stuff to judge. People... just want to feel superior."

Was he not guilty of it himself, sometimes? Usually he based it on martial ability, though.