I'm not from Philly nor is anyone in my family. We actually live 2 hours outside of Philly. But in all of the times I've been into the city we've never had a bad experience. That being said we aren't walking the city streets at night.
I'm not saying there aren't many good people in Philly. There are. All of my family and many of my friends still live there.
Im not a sports fan, so I can't comment on that aspect, but I know the neighborhoods (I have lived/worked/gone to school in almost every part of the city at some point) and they have declined very much in the past decade or so. People who only go into the city for concerts and sports aren't exposed to the decay. It saddens me to put down my "hometown" but it is the truth.