First of all, the so called “Birther” movement began when McCain was asked to prove his eligibilty, which he did. The “Birther” movement is simply the opposite side of that question i.e. Obama show yours. He still hasn’t and so the “Birther” movement is ongoing until he does. And it is a right and just cause for people who believe in the law and the Constitution.
If I remember correctly, questioning McCains place of birth was in response to republicans questioning Obamas eligibility...which, I have no proof, but believe, actually originated with some of the Clinton dirty tricksters.