Why are American pitbull terriers being accused of being mean?

Because they are mean ,inconsiderate people or they are training them for dog fights, which only mean inconsiderate people attend.

well some what that and many people are mean to pit bulls because they probably heard "oh well, some pit bull injured someone." or some say "stay away from pit bulls, they're dangerous animals." and so on.so basically,judging with out knowing what they're talking about. but pit bulls are really sweet at heart and I would know because I have a blue nosed American Pit Bull Terrier.Other wise like a lot of conversations on here...Bad Trainers creates Bad dogs.