Obama's "bitter" comments clearly leave a distaste in people's mouthes. While it's not an issue like abortion where many voters will say "I'm voting for X because he's pro-life," it's part of a larger macro-issue of personality. Some people WILL vote against Obama because he seems like an overly-educated, out-of-touch, elitist, black man. These comments reinforce this perception and will hurt him somewhat, but are hardly fatal anywhere, as we can see in the current polls.
Most of the rest of these non-issues either help Obama, are non-factors, or contribute insignificantly towards this macroissue of personality.
Right. Some voters fear we are electing Cornel West. Others fear we are electing Al Sharpton or Jesse Jackson. In fact, Obama doesn't fit into any mold -- any more than McCain does. But I agree -- Obama's "bitter" comment was and is worth criticism and scrutiny.