You replied to the guy in a pleasant manner, he is the one that left mumbling about who knows what. Let it go as you didn't reply in kind, and its fairly clear that he had no interest in a conversation by his actions when he turned away. As said, life is too short to allow his kind interfere with enjoying the outing and your bike.

My standard reply when someone like this guy is to tell them its my bike, I paid for it with my salary, and built it with my hands. When you sign my paycheck, pay for everything you see here, and show me that you own it free and clear, they can do and say anything you want with the bike. If any of this presents a problem they can suck eggs, or other things at their own choosing.

You have a really nice bike there, don't let a small minded individual upset you.

Bill