The entire article is dripping with sarcasm and irony. I’m pretty sure the last sentence is no different. He’s mocking Obama. Obama is talking down to people and inferring that those who oppose him are confused/naive/misguided morons because of one of these reasons:
1. “Smear Campaign”: He intentionally wants to paint them as such even though he knows there are legitimate and compelling to oppose his plan.
2. “Narcissist”: He believes in health-reform/etc. and thinks it really is in the best interests of the country but believes that people disagree because they haven’t heard his arguments yet, are stubborn and just won’t listen to his arguments, have heard his arguments and didn’t hear them correctly, or are simply too stupid to understand them.
3. “Barry Gump”: He is a pure-hearted simpleton who only wants the best for us but can’t get his message across because all the bad people keep making up lies and distractions to keep the people from hearing the truth.
He can’t believe that he’s so widely disbelieved.