Why does he do this?

He's very sweet but also reminds me of the movie Coming to America with Eddie Murphy. There was a scene where Murphy's parents had an arranged marriage wife for him to meet for the first time. She was like your guy. When Murphy asked her--what's your favorite music she would answer whatever you like. And every question had the same answer. She had no opinion of anything. What you have to do is tell him that his answers are very sweet but you really want to get to know things about his interests and tastes. If he still won't answer then maybe you should stop communicating until he gets the point.