It's simple enough. Much like the nice little spin move that Obama made at last Thursday's debate, when she insults Obama's oratory and message (such as her little sarcastic speech about the clouds parting and everyone uniting), she insults the millions of staunch Obama supporters that would otherwise vote for her in the general election if Obama didn't win the nomination. She's alienating core members of her party - namely, all of Obama's key demographics that she NEEDS to get her a win in the general election.
Do you see Obama slandering her personality? He attacks her on her policies - health care, NAFTA, tangible things that actually have some facts behind them (even if they have been distorted, which is admittedly a rather sad thing to see from the Obama camp). If he becomes the nominee, he's not going to have much trouble rallying up ex-Hillary supporters, or at least he's not going to have as much trouble as Hillary would have rallying up ex-Obama supporters. He's not going to have to explain that "Oh, that speech I gave that was mocking you? Yeah, I was JKing. You know how it is."
How long until you guys think the Hillary camp realizes the fatal flaw in her new campaign tactic? She's already gone through, what, four or five personality changes in the last month, from weepy Hillary to "it's an honor to be standing on a stage with Barack Obama" Hillary, who we just saw less than five days ago, to "Shame on you, Barack Obama" Hillary... what's next for her?
Maybe she'll turn into Optimus Prime. That would be sweeeet.