I know I'm reasonably new to the sport but it's fans like that why I'll never understand why everyone sits together. In soccer you have your home fans and the opposing teams fans sit in another section. I've not really seen anything kick off at NFL games during the actual game but it easily could with dickheads like that.Philly fans are even worse than Steelers fans, but you generally don't notice it because their teams are usually completely irrelevant.
Look up some of the videos from yesterday's game. Fights. Throwing beers at opposing fans. They've definitely earned the rep of being the biggest douchebags in the NFL.
I'm thinking of pulling for the Patriots too. Philly Fan is just so obnoxious.