I don't mean Southern voters are going to think, "Bush is so off-base...wait! Edwards said Dean hated Southerners! FUCK DEAN!". I mean he's contributed very substantially to that attitude, and his words WILL come into play, even if they're not associated with Edwards in the minds of the people.
It doesn't matter whether Edwards was a victim or not. Sharpton also assaulted Dean for that (obviously, for different reasons than Edwards cited), and I'm not sure who started it, but both were pretty bad. Sharpton is and always has been willing to exploit race for his own personal benefit to an extreme degree. I honestly had thought he had changed and become more rational and responsible, but his criticism of Dean--calling him racist, and saying he wanted the Klan to like him and whatnot--made me re-re-think and realise the old Sharpton isn't really gone after all. Fuck him, too.
Note that Carol Moseley-Braun, who is an intelligent person who is not a cheap, tawdry, race-baiter but IS black, would not attack Dean for the Confederate flag comment, so it's not like you can excuse Sharpton by saying, "Oh, he's black, he was in a RAGE thinking about the Confederate flag!!" or anything equally condescending.