It can be dangerous to watch a game in enemy territory. It's not unusual to see fans get into it with other fans at football stadiums and baseball parks. At basketball arenas though--at least the one the Utah Jazz play in for 41 games each season--you have to watch out for the mascot.
Jazz Bear has been known to mess with fans of the opposing team often taking it far enough that the person(s) get pretty angry--a lot like this guy.
I can't imagine this kind of thing is real. No employer in his right mind would be okay with someone antagonizing people to the point of violence.
Real or not it is still pretty funny--and that guy is an idiot for wasting a domestic beer he spent way too much money on.