You are committing the fallacy of substitution. You are equating the usage of the term under English Common law, to the meaning of the term under the American law.
English Law is Monarchical based. The foundational premise is that the King Rules by Divine right, and it is in accordance with nature that all his subjects should bear perpetual allegiance to him. It's philosophical authorities are people like Bracton, Coke, Hale, Foster, and Blackstone.
American Law is based on a different concept featuring the inherent rights of man as outlined in the reasoning of Philosophers such as Locke, Puffendorf, Vattel, Grotius, Rousseau and so on. Indeed, without our founders becoming aware of their ideas, we likely never would have broke away.
Both groups regard their own version of "natural philosophy" as correct and eternal. (Well, the English HAVE given up Jus Soli and Perpetual allegiance, so I guess it wasn't so eternal after all. ) It's just that we in this country picked a different basis for our conception of what is "natural."
Rights of a King v Rights of man. Here is how it was regarded by one man (Alexander Mcleod)in 1814.
England grabs people by any pretext, and makes of them "Subjects." This is why we fought the war of 1812. They were still counting Americans as THEIR SUBJECTS.