I disagree with your take -I don't see it being a question of moderation. You had many of those groups online (if not all of them) in the 90's and 00's. Unlike today, if you didn't like the forum you were on you could go to another one where you fit in.

There was a greater diversity of social gathering places.

Now -there's facebook, twitter, reddit and HN.

Moderation has ALWAYS been a factor and that's not what made the old internet better.

What made the old internet better was that it was open and more diverse (in terms of viewpoint and choices). The new internet is basically (on a social level) a few social media corporations which are becoming increasingly sterile.

Being on the internet and unmoderated doesn't mean you have to engage with everybody. The idea is that you get to choose what sort of conversation to engage in, and who to /ignore. Hardly different from "real life", except that the internet gives you a larger pool to engage with and better tools to deal with it.

I don't think you’re wrong in pointing out that the internet is likely more homogenous the further back in time we go. It’s a hard thing to be wrong about with respect to any scene. But I don't think I agree that it means that we must bend on principles of freedom of expression, digital civil liberties, and anti-censorship and anti-central control. And if definitely doesn't mean the internet wasn't possibly still the most diverse place on the planet even shortly after its inception. Now that the internet has taken the world stage, we must continually fight and push for the society we want to build, for what’s right, really. We must educate and in certain ways indoctrinate. Otherwise we risk losing our values to the swaths of normies—especially now that other cultures are vying for their own version of comfortable.