Not all Philly fans are the same, in fact every fan base has its jerks. I have met a few here in Vegas in fact.
There are more philly fans that are respectful to other fans than not. The ones who don't are just part of a *very* vocal minority who give the rest of us a bad name (you wont be seeing any twitter feeds or clips about the friendly nice Philly fans, you'll only see the bottom of the barrell). At the game last night there were maybe a 1000 max? There are millions of Philly fans, so lets not get caught up in hyperbole
I cant understand the Eagles chant at a hockey game either, makes no sense, and I certainly wouldn't have been a part of it.