It has to do with what every sports fan who follows sports as a whole knows: Philly fans are the most miserable, despicable, and ugly fans in any sport. Terry Francona (former Philly Manager and current Red Sox skipper) summed it up pretty well when he commented on the Phillies getting to the WS:
"There are some people I was really happy for..."
Fuck, I'd buy any Yankee fan a steak dinner before I'd shake the hand of a Phillies fan. :)
Most of the people most everywhere are nice people. The few assholes are the ones we remember and write about. Unfortunately, there is this mob effect that kicks in sometimes and like lemmings they jump over the cliff of stupidity.