You are completely wrong on this count.
If someone is in the US and NOT subject to US jurisdiction then the US can not arrest them, the US can not detain them, the US can not try them in any court, the US can not use any legal system to punish them. When a foreigner is in the US they are subject to the jurisdiction of the US. To not be subject to it would mean any foreigner entering the US could commit crimes and not be punished in any way shape or form. Your argument is ludicrous and completely ignorant of what jurisdiction means. When a foreign diplomat commits a crime, they are not subject to US law. The only recourse the US has is to request that their country remove them.
Every person born in the US is a person. That is what the Constitution says is the requirement to receive citizenship at birth. Unless they are a diplomat they are subject to US laws and therefore under US jurisdiction.
Many countries may not have birthright citizenship, but those countries don't have constitution that states that every person born in that country is a citizen. The only way to end birthright citizenship is to amend the US Constitution.