This used to be a selling point for me when I was younger, but increasingly I find myself not wanting to deal with poorly-moderated platforms. I can’t tell if it’s because the transgressive vulgarity that these platforms enable has lost its novelty as I’ve gotten older or because the median user has less to contribute. Every time I try to browse 4chan these days I find that half the posts are repulsive, basically pornographic representations of the world, and the other half is the product of psychosis (that is, the people making the posts likely need to be institutionalized).

There are a lot of people who have nothing to contribute to a conversation, and a lot of people who are actively detrimental to a conversation. It used to be that you would put up with the craziest ones for the benefit of finding novel and overlooked ideas, but as the internet has become more accessible, the former group now outnumbers the latter.

I would be inclined to think that the problem is that I just grew out of the shock value, but I see the same trend on almost every other platform, too.

This is good sometimes but also horrible sometimes, because reputation exists for a reason. It's a filter, and if you have terabytes of information around which has mostly garbage quality you need filters if you want to make it useful. Of course, reputation does not solve the problem entirely, but at least it makes some steps towards the solution. Otherwise, you're basically on your own against the ocean of garbage, and not many people can really handle that.

Agreed. I would go so far as to say all the ills of modern social media are because of ranked platforms, such as upvote/downvote-based, or like-based. They turn into echo chambers, that promote witty one-liners over nuance, and any sort of controversial position is effectively censored.

That said, HN functions decently well, though in some ways it is even worse in the censoring the outliers.

Hard disagree. Finding anything of quality on 4chan is like searching for gold nuggets by hand in a mountain of radioactive poop. The only times I've ever seen anything useful in there is when someone else has already done the hard work of curating a post.

The core reason why HN is superior (IMO) is the curation and the moderation.

That is heretical now, unimaginable to huge swaths of the Internet.