Do you know of any court ruling that differentiates between a Citizen of the United Ststes AT birth and a Citizen of the United Sates BY birth?
Using your own words, a person who at a point in time (birth) was a Citizen of the United States doesn’t seem in any way distinct from a person whose birth caused them to be a citizen or a person whose citizenship was caused by the circumstances of their birth.
A person born in country to citizen has always been a citizen in law, without statute.
Great question.
I'd bet there is none.
Using your own words, a person who at a point in time (birth) was a Citizen of the United States doesn’t seem in any way distinct from a person whose birth caused them to be a citizen or a person whose citizenship was caused by the circumstances of their birth.
Or, to put it another way:
If a person isn't a citizen by birth, then how is it even possible for that person to be a citizen at birth?
I just don't see that it is. And I don't see that any judge or court would EVER see it differently.