Why do I hate the words "fictional" and "fairy tale"?

I am not a Christian, nor am I even a theist. Let's just get that out of the way.

Anyway, I browse the R&S section a lot, and naturally I see a lot of atheists answering questions in which they deny the existence of god. That's all fine and dandy, but the only answers that irritate me are when people use the words "fictional" or "fairy tale". I don't know why, these two phrases bug the hell out of me. It makes me think of the person that uses them as being incredibly pretentious, as well as idiotic. Things like "doesn't exist" "isn't real" or "fake" don't bother me, but those two do. Sky daddy is annoying too, but it's not nearly as bad. Why do those specific phrases bother me?