She's trying to prove she's a good sport who can take a joke at her expense. I believe the hope is that, if people believe this, they will forgive her for championing ignorance and mongering hate.
I hate to say it, but I'm really worried about Maine. A few weeks ago, I had faith in this surprisingly Democratic state, but I had forgotten the deep streak of racism that flows within the average Mainer. I had forgotten the numerous arguments I've had with young white men here who complain about people of various hues taking their jobs--a particularly jaw-droppingly stupid claim given that there are only about seven blacks and Hispanics in the state. I had forgotten that when Jesse Jackson won here it was semimeaningless, since caucuses attract only the most active Democrats. Now I'm hearing that McCain-Palin signs are everywhere. Worse, when someone is asked what s/he thinks of Obama, the response all too often is, "Oh, he seems like a nice guy, but . . ." Mostly no one dares complete the sentence, but its conclusion is clear.
If Obama loses (and more and more I'm thinking he will), anyone who attributes this to anything but race (or "cultural differences," as the code now goes) is naive, dumb, or a big fat liar.