That was going to be my reply. Why hide it? Why hide your birth certificate? Makes some bitter white people who cling to their guns and religion suspicious.
When you were a kid, did you ever continue to deny that you had eaten the cookies when the crumbs were on your face? Did you continue to maintain your innocence even when all your siblings and three of the neighbour kids saw you do it?
When you were in school and the teacher asked if you wrote that word on the blackboard, and you did, did you deny it even though the whole class saw you do it? Did you continue to deny it even when the teacher said if the culprit didn’t speak up, the whole class would serve detention?
That’s Obama. If what he did was broadcast on closed circuit teevee and the entire world saw him do it — he would continue to deny that he did.
For the same reason the kid denies he wrote the word or ate the cookies when everybody knows he did — because once he has lied, he can only choose to stick to his lie or to humiliate himself by admitting he lied.