It's actually quite simple... The reason the McCain campaign looks silly is because they planted someone at a rally who falsely represented himself, and they are all continuing to falsely represent him, when we all know that he is not what he said he was.
There is nothing wrong with asking questions of the candidates. Good for him that he got the chance. But, he did not need to misrepresent himself to ask the question he did. He is living a fantasy, and allowing that fantasy to influence his decisions. And since the McCain campaign continues to trot him about, it makes it seem as though they are all for misrepresentations. Not really a good thing for a presidential candidate, if you ask me.