Below, Katie discusses Joe Biden's race-baiting comments, and the fact that the Obama campaign condones them. Get used to this kind of stuff -- Obama-Biden knows that Democrats lag in intensity this election, and they're going to be desperate to find reasons to drive voters to the polls.
All that being said, the remark is as stupid politically as it is substantively.
Keep in mind that comments this incendiary spread far beyond their intended audience, especially in this age of the internet. Whatever perceived benefit they may confer upon Obama-Biden among African-Americans, I'd bet, is more than offset by the disgust they elicit from other voters (including African-Americans who are tired of being played for chumps by the Democrats). And among the most offended, I suspect, are the independent, "moderate" voters who value civil discourse highly -- along with all the other Americans tired of spurious claims of racism. If Obama-Biden (the erstwhile "purple America" and "hope and change" ticket) try to divide Americans along racial lines, chances are it will do more to hurt them than to injure Romney-Ryan.