No, you are arguing the converse; That someone born in a nation, yet raised in another nation will still have loyalty to the nation he was born in rather than the nation he was raised in. In either case, the loyalty is suspect. Not so for people born and raised by loyal parents in their own country. Can you not see why you wouldn't want such a situation? So did the founders.
The Manchurian Candidate was a natural born citizen by even the strictest definition.
Technically perhaps, but not in spirit. The notion of a disloyal fraud is still apt.
So wait: now you're arguing that a president has to not only be born in the US, and not only be born of citizen parents, but also raised in the US? Are you claiming that opinion was expressed by the Founders somewhere?
Besides, the part where you say "you are arguing the converse; That someone born in a nation, yet raised in another nation will still have loyalty to the nation he was born in rather than the nation he was raised in"--that was your argument! You wrote, of your hostage royalty example, "their loyalty was always assumed to be to that of the Family and Nation that sent them, rather than the one they lived in"! Are you now disavowing that argument? I can't keep track.