All of this is simple distraction. Your "nobody was ever asked" is total hogwash. And then using it to race bait makes you at the very least baiter-curious. What's the matter? Ashamed of your baitey-ness?
Nobody has ever asked. And it isn't to difficult to figure out why the fact that Obama is black may have something to do with his unwillingness to release it.
And really nobody did ever ask to see McCain's birth certificate to prove his eligibility to be president. In fact, the very document that you linked to was obtained by a guy trying to prove that McCain was not a natural born citizen and was used as evidence to prove his ineligibility to be president, not to prove his eligibility.