We are amall group primates, it's our nature. Us vs Them. In and Out groups. Everyone is a victim of it.

Maybe your narrow-minded group believes in in- and out-groups, but not mine!

Ahh. You mean your "in-group" of people who don't believe in "in-groups".

This is tongue-in-cheek. :)

There was a time I would lamented the need to be so explicit. But now, I'm just grateful the point got across. Communication seems to happen less and less reliably, with more error modes with greater negative emotional impact, and I worry that this implies the existence of some sort of inevitable drift between my brain and other people's brains. And I'm not sure if the solution is to bridge the gap, or just keep going and learn to accept inane resistance with some combination of stoicism and resigned amusement.

You will burn in sparrow-hell!

https://pbs.twimg.com/media/EF3JLYwXUAAqDPP.jpg

Not sure how it applies, but it is funny in its own right. I mean, it's a good example of in- and out-groups, but it's not a good example of a group that denies the existence of out-groups (which is admittedly more self-referential and weird. You know, like an xkcd cartoon.)

It's also our nature to beat each other up on occasion. That doesn't mean we have to be victim of it.

Yes, absolutely. People are multidimensional. Most people may not care for your particular captivating niche interest, but some will find your excitement about it interesting and enjoy your excitement about it. And you can reciprocate that feeling towards their niche interests (almost everyone has at least one). Toss everyone who doesn't care about your thing into the same "normie" pile at your peril.