McCain was born in the Panama Canal Zone, a US Territory at the time.
Are you saying that persons born to Panamian-citizens in the Canal Zone were U.S. citizens by place of birth?
Only persons born to U.S. citizen parents there were U.S. citizens at birth. For Constitutional purposes, it was “overseas.”
https://en.wikipedia.org/wiki/Panama_Canal_Zone#Citizenship
Now, think of Guantanamo. Do you see why detainees are sent there? Being leased and not sovereign U.S. territory, it’s in a kind of a Constitutional no man’s land.