I've never really followed sports, but why do its crowds always act so barbaric? As much as our media likes to point large, foam fingers at the gaming industry, I think there's enough evidence to say they're may be something psychologically wrong with a lot of sports fans, collectively.
There are only riots like this after a major championship, and most of the time, the rioting is being done by people who couldn't care less about the game. They were just waiting for an excuse to riot. Also, despite what many are saying, it happens in nearly every city after a championship. This incident wasn't unique to Philadelphia.