Why ”where are you from?” is a taboo question.

Hello again, I have just returned from a skiing trip in France and I met an old French man in a small village who thought he had the right to interrogate me and find out what kind of Asian I was. It turned quite nasty because I felt it was extremely offensive to be interrogated like that when I was simply minding my own business. Let me explain how I would’ve engaged someone. I have only just met.