The pollsters, that's who. David Graham is right. But he's more right than he realizes. How many of us scrutinize the pollsters' questions? Not that many, I bet. Very often, the questions pollsters ask are begging an answer that is misleading at best.
PPP, which is a Democratic firm, is sometimes maligned for being an unreliable pollster, but in this case the biggest problem is that they're asking the question at all. The belief that Obama is a Muslim, like the belief that he is somehow not an American citizen, is pernicious and flatly wrong. It has also been rejected by the vast majority of the American body politic, although there are some glaring examples of politicians who flirt with it to score political points. But if the goal is to fight mistaken beliefs, this is the wrong way to do it. The Dartmouth political scientist Brendan Nyhan has researched misperceptions and conspiracy-theory belief in America politics. In particular, he and colleague Jason Reifler have found that false ideas, once introduced, are very hard to get rid of. One especially bad way to fight them is to reiterate them. ...David Graham, The Atlantic
About Obama being a Muslim. Just ask the question and you're perpetuating a nasty myth. You don't have to go as far as asking "Are you one of those backwoods unpeople who believes Obama is a Muslim?" to get the joyful answer, "Yes! Yes, of course." You could ask "Did Obama spring from the belly-button of a crocodile?" and you might even find four Liberty University conservatives who'd ask, "Obama who?"
The problem is not Obama, crocodiles, or Muslims -- or even Liberty University. This is really about what it means to be a conservative and what is required of you to maintain membership in that clan.