For the record, I don't believe Obama is a Muslim. But Mark Davis makes excellent points concerning why many doubt or are uncertain of Obama's claims of Christianity. He points out the media's charge that those identifying him as a Muslim have reached that conclusion "contrary to the facts." But something does not become a fact simply because a politician you like says it. They should use the phrase "contrary to the president's claims".
If one judges his veracity by his actions rather than words, concluding that we're being lied to once again is not unreasonable. Davis writes
I have seen him defend a mosque near Ground Zero while asking Georgetown University to cover up Christian imagery for his visit. I have seen him openly embrace Ramadan while keeping the trappings of his supposed Christian faith obscured. And I have seen him adopt an arrogance toward Israel that any Palestinian would love.
Does this make him a Muslim? Not any more than my affinity for Israel makes me a Jew. But if some "Americans examine his actions and choose to doubt his claim to Christianity, it is not as though his governance hasn't given them a sound basis for choosing not to take him at his word."