They are delusional as hell. Luna was a child, so it's more forgivable, but Luna's father is a mature adult, yet he still believes some crazy stuff. At least I'm not as blind as Xenophilius and the people who think he isn't delusional.
Yes, that's true, but Xenophilius was the chief editor of a hoax newspaper. If he wasn't delusional, he would be a greedy and manipulative news editor.
I'm still sticking with delusional. His beliefs were way to crazy and out-of-the-point. A believer might believe in one or two things that are kinda unbelievable, but they'll put rational thought in it. Xenophilius believed in countless crazy things that made no sense.