He was born on American soil, thus a natural born citizen. His parents were immigrating here to live and weren’t to my knowledge government officials from abroad who just happened to be here, so no exception in that regard.
We might not like it that any baby born on US soil(except for exceptions) is an American citizen by birth, but that is and has been immigration law.
“He was born on American soil, thus a natural born citizen.” The words of the men who wrote the Constitution do not agree with your assessment. I understand why you waqnt that to be the reality, but it is not. Natural born citizen is a special category for defining a person born of TWO American citizen parents. There is still discussion as to whether such a child of TWO American citizen parents has to be born on U.S. soil, also, but I am not addressing that presently, just the TWO American citizen parents.