I mean, they almost killed a guy. And when I was there in 2008 someone took my hat off my head and threw it from the upper deck as the Phillies clinched the series. Then he said it was for my own protection and I think he was half-sincere (I had already not worn it as I was walking there from Echo Park).
But of course there are bad drunk fans everywhere. I've seen some things at Madison Square Garden and I've also seen bad Flyers fans on the road.
I've heard stories about Giants and Padres fans too. The times I have seen the Phillies play in San Francisco, some fans have been nasty. I recall reading that a Padres fan shoved Ryne Sandberg's father down an escalator in the 1984 NLCS. A Dodgers fan got stabbed to death after a a Giants-Dodgers game in San Francisco in 2013. So much for laid-back California.
Yet, Philadelphia fans are America's barbarians. The other three teams take the blame for what Eagles fans do.