Earlier quoted context omitted.
You forgot the end of the story: "I'm denying you the ability to enter the country. Next time you let me see everything instead of being a wise guy."
If you are an American citizen, can they prevent you from entering the country? I understand they can delay you, but I don't think it can be indefinite.
They can deny foreigners, but I've always read that they cannot deny Americans in unless their citizenship gets revoked, I guess.