The Constitution does not say who is responsible for checking the candidate's credentials. It would take legislation passed by Congress to do that. And I'm not aware of any such law being on the books. Maybe there should be, but currently there isn't. So Obama's qualifications or lack there of fall into a grey area. Maybe he is qualified. Maybe he isn't. But he isn't required to provide any more than he has, and there is nobody tasked with looking into it.
I just proved my argument. Ignore the truth or misinterpret all you want on that eight-hour shift of yours.