Part of the reason is that many of the people asking for the documents are unhinged. The very idea that the documents would somehow prove a birth anywhere other than Hawaii is absurd. Thus when people demanding documents go around saying they suspect he was born in Kenya, sane people dismiss them.
He isn’t being transparent, is he?
No, and that's a legitimate campaign issue (though until 2012 it's a bit moot). Too bad all the birther nonsense distracted people from it when it might have made a difference.
So rather than focusing your attention on trashing “birthers”, why not take up the issue of his long list of hidden documents. As Rush is saying right now, we have a president who doesn’t want to tell us who he is.