I agree with your take on it ExTxMarine. I’m not an attorney, but this is my take on the 14th Amendment, in particular the section you address.
Persons visiting in the United States, are not U.S. Subjects. They are the subjects of the nation where they are citizens.
They are subjects of another country from a citizenship standpoint. But visiting here is not a license to disobey our laws. Any person, regardless of citizenship, who breaks the law in the U.S. can be arrested, tried, and jailed. Any American who breaks the laws in a foreign country can have the same fate. Subject to our jurisdiction means subject to our laws and the penalty for breaking them. Every person visiting, legally or illegally, falls into that category. With the exception of those under diplomatic immunity.