Assuming that Bill Peduto is being sincere in dropping out of the Democratic primary because he doesn't like the negative tone of the campaign, then I have three words for him: Boo-friggin-who.
You don't get into politics these days unless you are willing to get your knuckles bloody now and then. Lamentable, perhaps, but that's the way it is. Just ask President Kerry. Besides, Peduto is running against an incumbent. Any time an incumbent runs for re-election the race is a referendum on their performance in office. (I realize Luke Ravenstahl isn't technical running for re-election, but the principal holds.) And I never heard Peduto issue a call for all those bloggers who were supporting him so vociferously to stop their daily attacks on the mayor.
Don't get me wrong--I was pretty convinced that Peduto was in for a thumping come the primary, but I was still holding out hope for an upset. Even if Peduto gets into the general election as an independent, I don't see much chance, absent a complete meltdown by the mayor over the summer, for Peduto to prevail.