I’d happily discuss The Protomen with you at length. Oh, you don’t know who they are? Well, I certainly am not going to explain to some random semi-stranger that I very much enjoy a band whose major work is a Megaman-themed rock opera, that’s just not a conversation I want to have. I can usually feel them judging me the whole time.

I don't think you're in the wrong. You're entitled how you want to spend your energy.

But if the other person shows interest, I'd love to give them a "tour" of whatever band or genre. And I like when people show me stuff they're into, sometimes.

Sometimes because that "giving a tour" activity is a skill. Like one person could give a summary of the protomen really interesting, and someone else might just infodump it in an overwhelming way. Also picking up on when they're legitimately interested vs being polite is a skill.

I hope you won't take my comment the wrong way, I'm trying to be friendly but this can be a sensitive topic. Also disclaimer, I do think if you're American the vibe there is very different, I'm writing from an European perspective which I suspect you might be too considering the genres listed (if not, maybe consider moving here haha).

I get what you're trying to say but you're probably shielding yourself off from finding common grounds with a lot of people. I don't think any of what you listed is so obscure that no one knows about them, and despite your protest, I think you do think your taste is very special and unique and no one can understand you. All of these genres have huge followings (have you seen the crowds at hard style festivals? Lol, that's a genre a lot of people in underground electronic music consider mainstream).

Assuming they're not just the kind of people listening to the radio or top 40 stuff, even if they don't know the Megaman rock opera band (which, hey, I heard of it as it turns out, though I couldn't have named them), they might be interested in learning more about it. But it sounds like you've made up your mind that not only could no one else possibly have such unique and peculiar taste as you, but that no one (or almost no one) would even be interested in expanding their own musical horizons.

Either you only know/meet really shitty people (unlikely) or this is a construct you've built into your mind. I get it though, I used to have similar feelings towards the general public when I was younger (though I always did have access to crowds that would share at least one or more genre with me) but with age I realized I just don't give a fuck what people think and I'll listen and happily discuss whatever I like (and, gasp, yes, that also includes some mainstream things!) with anyone that's interested, whether they're already versed into the genre or not. I've put on a lot of people to a lot of good stuff like this over the years to the point they became regular listeners or even buying vinyl of it etc, and the same happened to me.