Personally I agree with the writer thing.
From AIM chat rooms back in the day, to forums, to Twitter, I've always hung around a lot of nerd spaces where writers and creatives frequent, and they tend towards being pretty unreasonable.
Video game writers, fanfic writers, comic book writers (ESPECIALLY comic book writers, holy crap)...the majority of them I've interacted with online I've seen tend towards frequent unpleasant interactions.
Could be that it's only the ones that frequently engage withe public that are that way....but that's kind of a chicken or the egg situation.