Well, someone on this forum said they'd lost any respect that they might have had for me because I'd mentioned I liked 80's rock. LOL!
I listen to all kinds of music - classical, pop, rock, j-rock, folk music, metal, country, etc - but that's the only time that I can recall that someone has tried to put me down for the music I listen to. Well, my family has looked at me funny occasionally in regards to the Japanese music, but I now have a niece who listens to it more, ha!
I tend not to focus on the genre that much and more the songs themselves. I'm definitely not a fan of most techno/trance/similar music for example, but I've heard a few I liked. Which is why I won't diss someone listening to pop music but when I see a teen girl I know raving about a new Justin Bieber song I shudder with horror.
I feel for you OP, and I can't believe that guy's nerve. You have every right to listen to whatever music you like in public as long as you're wearing head phones (which you were). The other day on the bus a guy was playing loud Spanish music on his phone to his kid without headphones; if someone had objected to that they'd be in the right(IMO), but no one did. (Swedes, you know. We're not big on confrontation.)
Sorry for the long post =(