Sometimes I get tired of talking about this (and probably my longtime readers get tired of me talking about it too) but fans in general (and anime fans in particular) don't have a very good grip on the annoying and confusing history of fandom and how it dealt with the wider world of pop culture. (Short verion: cowering retreat.) Also, since a lot of the new fans are coming into a community notorious for its horrible social skills, I guess it's not too surprising that some of them are reacting exactly like the people they hated in the culture they were trying to get away from. I will concede that not all the bad behavior is coming from "veteran" fans, either; our winning the culture wars has increased the number of divas, drunks, and other asshats who never learned how to be polite at our conventions, with predictable results.
The problem from a convention staffing standpoint is that there's really not much you can do, officially, to deal with stupid cruelty like this until it gets completely out of hand and blows up into epic drama with the potential to completely ruin the convention. I had to deal with this one year at Detour; one young lady (we'll call her D) got to a point where she was so sick and tired of the treatment she was getting from her "friends" in her school anime club that she ditched them - which led to panic when their parent chaperone realized that one of her charges had disappeared. An APB within the convention followed, and Security found D without too much trouble - she turned out to be sitting in an out-of-the-way corner of the hotel quietly talking with somebody she'd met, who was absolutely terrified to be accosted by convention security and "invited" up to Ops for a short conversation with the Chairman. When I realized there was no crisis, just drama, I damn near blew a gasket. I wound up having a "come to Jesus" talk with the club members responsible for all this BS, and I was in full brimstone-and-hellfire mode. Fortunately the chaperone was on board with my little sermon, but I would have lit into them anyway. Back then, my mantra was "the convention comes first", and if I'd had to blacklist every one of those spoiled little coeds, I would have done it in a heartbeat, because the alternative would have been to open up the convention to all manner of ugly rumors and liability. And that's about all you can do, unfortunately, because the kind of people that do stupid, cruel things like that don't respond to anything less.
I ran into D a year later at Convergence when I was working in Programming, and she thanked me for reorienting those girls' headspaces and giving her a boost to her self-confidence. Hopefully she's still doing okay.