51% of Republicans think Obama is Muslim, what explains this ignorance of facts amongst Republicans?

A recent poll shows how ignorance is rampant in the Republican party. They even showed on Fox how this ignorance is live with a poll of a caucus in Iowa. Facts are facts and Obama is not Muslim yet there are those who are not educated to this fact. Just because there are many ignorant to facts, it doersn't change them. Does this ignorance to facts bode well of things to come in the GOP? Is Fox news a reason for this ignorance on the Right?