This is really dumb. This "allegiance" isn't about a state of mind. No law can control that. And there is no "sole" in "natural born citizen".
“And there is no “sole” in “natural born citizen”.”
Natural born means born of citizen parents, inserted into the Constitution by our birther Founders. They listed three requirements for being president, and that is one of them. So, although it means nothing to you, it obviously did to them. And, it is the law.
There are lots of natural born citizens who have exactly zero allegiance to the USA. Most of them are democRats.