I do indeed share at least one other of your tastes in music. But I also argue that many who share it with us probably share it for the aforementioned reason.
But this is just the same kind of thing you're *accusing* the other people who like Beefheart of. "Oh, *I* just happen to like Beefheart. It's those other people, they don't get him like I do. They're just *pretending* to like his music, so they can be cool like me. They probably really like Adele or something. Posers."
I agree with Theydon Bois on this one -- and in fact it was the experience of reading all those "everyone's just *pretending* to like Trout Mask Replica, no-one could really like it" articles that made me so annoyed by this argument as well. (And really? *Trout Mask Replica* is unlistenably strange and weird? It's just what you get when you're playing Chess-style blues but also listen to a few Ornette Coleman records... One interesting thing for me was when a friend, who's mostly into fairly soft pop music, listened to Safe As Milk for the first time -- his response was "It sounds like the Monkees". And he's right, it does...)
I keep seeing this claim, that people pretend to like music they don't really like, in order to impress other people. What I've never seen is an example of anyone who's actually impressed by that -- at least, anyone out of their teens. I've seen a hell of a lot of people who mock and scorn people they claim are doing that, though.
I've said, lots of times to lots of people "I like Trout Mask Replica" or "I like The Beach Boys Love You", and not once has anyone found it impressive. Why would someone keep doing something like that to impress people, if no-one's impressed by it? Occam's razor says they're not, and that even people you find annoying can be honest about their musical tastes.