Isn't topical subcommunities just Reddit?

The userbase overlap is probably > 50%. To many people HN is just another subreddit.

Personally, I'm more interested in the think-pieces than the actual news.

(And I could very much do without the content that revolves around US politics. Even if it draws me in sometimes.)

Lobste.rs provides that distinction.

And it's invite-only, so it's hardly an alternative.

well, it takes around 20 minutes to get an invite, so hardly a problem if you prefer only tech articles

How exactly does it take 20 minutes to get an invite? I have not tried it, but I can't see how that would be easy.

I got mine in about that time, joined their IRC and asked for an invite, someone DM'd me, asked me a couple of questions and sent me the invite. This was about 7 years ago when there as a lot less people, so I imagine it should be easier now.

No idea. Read only is good enough.

A socially awkward speakeasy with deranged moderation?

Where do I sign up?

A forum that is exclusionary-by-design has already failed.