“People used to understand this because they used to actually teach this when they actually taught American History and Civics instead of Social Studies .”
And yet not one person has ever been able to find one example of a Civics text book from any period that supports your view. Why do you think that is?
How about from the pen of the man who "coined the term" in the 18th century and understood by the signers of the Constitution (1787)....and the American populace at the time.
Emmerich de Vattel from the "Law of Nations" (1758).
§ 212. Of the citizens and natives.
“The citizens are the members of the civil society; bound to this society by certain duties, and subject to its authority, they equally participate in its advantages. The natives, or natural-born citizens, are those born in the country, of parents who are citizens. As the society cannot exist and perpetuate itself otherwise than by the children of the citizens, those children naturally follow the condition of their fathers, and succeed to all their rights. The society is supposed to desire this, in consequence of what it owes to its own preservation; and it is presumed, as matter of course, that each citizen, on entering into society, reserves to his children the right of becoming members of it. The country of the fathers is therefore that of the children; and these become true citizens merely by their tacit consent. We shall soon see whether, on their coming to the years of discretion, they may renounce their right, and what they owe to the society in which they were born. I say, that, in order to be of the country, it is necessary that a person be born of a father who is a citizen; for, if he is born there of a foreigner, it will be only the place of his birth, and not his country.”
Now.....why would this readily understood term from a publication read throughout the civilized world at the time.....magically become known as something else entirely different in a short 29 years?