forty some year old dudes still dreaming of rock and roll in the 60's probably
yeah, you are right, they were probably very entertained by your reaction.
I don't know, there are things you can do.
1. just agree with everything they say and tell them you are wasting your money on bullshit releases of some guys' musical masturbation.
2. put on some merzbow and let them talk while waiting for them to walk out of your room. if they confront you later about the incident, tell them you wanted some silent moments.
3. tell them you just wanna laid this beautiful artsy girl who is heavily into avant garde music. but you have to build credibility for the girl to like you.
4. tell them you actually like john tesh, Kenny G and dave sandborn better, but hate to admit it.
5. steer the conversation to their clothing like "nice shirt, by the way, where did you get it?"
6. hire a hitman

just kidding
I don't know. usually I try not to talk about shit like that with my relatives and parents.