Well, as a B i think everyone else is lying to themselves and we are all actually bisexual...
I'm joking, but i know people who are completely for that stuff, because everyone thinks they've got the correct 'sexuality', that's a reason why some heterosexual's hassle others so much, and because the some LG can't hassle the straight people (due to obvious biological imperative), they instead hassle the B&T, while B's generally hassle everyone else if they're like that.
My point is, that like every other 'community'(geeks, certain races etc.), it's far more complicated than one group hating on another group, though that's already been pointed out multiple times.
However, because you seem to be interested, remember that the only thing in common with many in the group is their sexuality, not the best of interests to base a group on, so there's going to be a lot of differing opinions on everything. I personally stopped going to my community because i had Nothing in common with anyone else there, and that wasn't fun.