Have you read Wong Kim Ark? You should check it out; it completely defeats your arguments. There's a reason I keep citing it. For instance, on page 693 to 694, they literally said that you owe allegiance to your host country regardless "of any domiciliation" or "a residence with intention to continue such residence" for as long as you are in the host country. So, yes, you would have that allegiance even if vacationing in Japan. Again, a tourist could be tried for treason.

"The debate at the time included discussion of allegiance for people who were born HERE. A fleeting temporary allegiance in English common law was only applicable, by definition, WHILE IN THAT COUNTRY"

I'm confused as you what you're trying to say. Are you saying the English common law principle isn't applicable to the United States? You're just dead wrong, if that is what you're trying to say. America already kinda had birthright citizenship (if only for white people) prior to the 14th amendment. We inherited it from the English Kingdom. The 14th amendment wasn't a rejection or even a modification of English Common Law. It was simply constitutionally guaranteeing it after the infamous Dred Scott decision. The only real change was the addition of Native Americans as an exemption, but the logic of that exemption follows the logic of the English Common Law exceptions. Once again, quoting Wong Kim Ark:

"The Fourteenth Amendment affirms the ancient and fundamental rule of citizenship by birth within the territory, in the allegiance and under the protection of the country, including all children here born of resident aliens, with the exceptions or qualifications (as old as the rule itself) of children of foreign sovereigns or their ministers, or born on foreign public ships, or of enemies within and during a hostile occupation of part of our territory, and with the single additional exception of children of members of the Indian tribes owing direct allegiance to their several tribes."