I suppose you could answer each question "I decline to answer that question, further to my rights under the Fifth Amendment to the United States Constitution. Am I free to go? If not, please explain why I am not being permitted to re-enter my country."

After two or three goes, ask for a supervisor and an LEO.

As for the reason why, chances are you have a similar name to someone who's wanted, or suspicious, or was rude to a TSA clerk seven years ago.