I think you have to look at what's happened in the campaign to understand this. They cant run on their record, so they spent the whole campaign demonizing Romney. Then he showed up at the debate and steamrolled Obama. They started getting behind in the polls and switched back to demonization about what a liar he is - only this time it won't work because Romney showed up and looked qualified, knowledgable, honest, and presidential. People know he isn't satan. Their campaign strategy was based upon that.
As Krauthammer pointed out afterward, painting Romney as demonic and evil isn't going to wash with the public because they can see through it. The guy doesn't even drink coffee.
Sesame Street is a welcome distraction that allows them to gather themselves and attempt to reposition their campaign. They'd much rather talk about this nonsense than where the campaign is today or what the poll numbers are doing, or what's going on in the Middle East.