If he'd read what I wrote, he'd certainly see that my point was that ridiculous claims are easy to make, but that the facts often betray the assertion.

It's easy to say that Sidney is a foreigner, which he TECHNICALLY would be...he was born outside of the U.S. but, of course, common wisdom would dictate that he's a US citizen, since he was born on a military base.

The constitution requires that the president be “a natural born citizen"  It doesn't say "born here."

There are two ways to become a citizen. First, if you are not a citizen you can be naturalized.  

Second, if you are born one. - i.e., "natural born."  People born to U.S. citizens who are temporarily overseas are automatically citizens. They are born citizens, naturally.

That is why they never have to go through immigration the first time the come to the U.S.
That is why they never have to apply for citizenship to vote, serve on juries, or get any other benefit of citizenship.

They just have always been recognized as citizens, regardless of where they are born.

The reason from this stems from the concept of a citizen being "subject to the juridsiction" of the country, as reflected in the 14th Amendment.

American citizens are still subject to the jurisidiction of the U.S., even when they are overseas.  That is why they can't engage in sex acts with children in Thailand, even though it may be legal there.  (There are scores of other things Americans can't do overseas, even though they might be legal in that particular country.)

If you are born to U.S. parents, you are subject to the jurisdiction. Because they don't have to be naturalized and because they are subject to U.S. jurisdiction, they are born citizens.

A baby of an American couple born either on an American Airlines flight or a Brit Airways flight does not have be be natualize and is subject to the laws and jurisdication.

Therefore he can become president.

Hope that helps.