@TRShottie
Under normal circumstances I would agree, but in a situation where you are constantly reminded that you are different from those around you; you become hyper aware of those differences yourself. So Iruma saying this is not out of the question.
As for Kirio; demons live in a world with magic, and if you've noticed they refer to themselves as demons more than a normal human in the human world would refer to themselves as such. Also Kirio and Baal are a group whose purpose is to return the underworld to how it used to be. (I'm assuming that eating humans wasn't restricted then seeing as how Amelie's dad is part of a security group that was probably created by Delkira-sama) And since Baal mentioned so casually that Sullivan went to the human world, I am also assuming that Kirio already knew of the existence of the human world and thus humans. He'd just never met one before. So even though humans are considered fairy tale creatures, Kirio has remarked that Iruma is strange and already thinks that (for a demon) he's awfully kind, meak, and un-demon-like.
That was more rant-y than I thought it be, but that's just my two cents on the matter.