Absolutely.
The main reason why there’s a perception of a fandom being crappy is The GIFT.
For those of your who aren’t familiar with the term, it’s John Gabriel’s (Penny Arcade) Greater Internet Fuckwad Theory.
You take a normal person, give them anonymity and an audience, and they will behave like a total fuckwad.
The thing with fandoms is that within the fandom, you have an audience, and a degree of anonymity – Enough to make you think no one can get you through the screen, and not enough so that you don’t get recognition.
The audience and the distance of the internet and/or the protection of a group makes people bold, it makes them crave judgement from others, good or bad, and thus it makes them do stupid things.
The internet and society rarely rewards people for being good and generous, I don’t really find it surprising that negative attitudes are more prevalent.
But it’s up to each one of us to change that.