I have never argued that Obama is not a natural born citizen because he was a British Subject at birth.
The only argument I have ever made against his being a Natural Born Citizen is that he was not a U.S. citizen at birth.
As you will notice, in the quotation you posted, Obama’s birth in Hawaii is accepted ONLY for the sake of argument. It is not asserted as a fact.
And, of course, there is no EVIDENCE that Obama was born in Hawaii, there are only assertions to that effect by various people.
Once again, a data dump that is completely beside the point.
No Trier of Fact (judge, jury or state Elections Board) can confirm any person’s birth, not even their own.
Triers of Fact have to take the word of the birth certificate issuing authority and in this case, that is the Hawaii Department of Health. The standard used is that a birth certificate which bears an official stamp and an authorizing signature is presumed to be accurate in the absence of probative evidence to the contrary. That is known as a “Self-authenticating Document.” [Federal Rule of Evidence 902: Evidence that is Self-Authenticating].