"Natural born citizen" is a subset of the group "citizen"; those "citizens" who are born in the country, to parents who are both "citizens" themselves.
What then can we make of the argument that “citizen” is its own category apart from “natural born citizen”? I don't make much of it, as it is ridiculous. That is the point of my post, that “citizen” is not its own separate category - it is inclusive of THREE types of U.S. citizen mentioned in the Constitution.