It all started in Captain America (2005) #7-8. Cap tracked a kidnapped Sharon Carter to the City of Brotherly Love, only to be caught in a trap by the Red Skull. A trap that blew up a section of Center City. Not to mention, a brainwashed Winter Soldier pressed the detonator. Not cool, Bucky. And do not hold your breath hoping this scene makes it into “Captain America 2: The Winter Soldier,” despite the fact that the film is adapting this story. That would show Philly too much respect.
Shortly after this fair city got blown up (and with zero reference to that previous event), the U.S. Agent, an edgier former Captain America, takes a shot at Philly in a story from Civil War: Choosing Sides. Despite the fact that U.S. Agent would be the perfect hero to base in Philadelphia, being a patriotic hero with attitude, he goes and says he never wants to return here. The nerve! Just because some S.H.I.E.L.D. agents are trying to kill him? Suck it up, dude.