I think the community on this site these days, much like other comment sections on the web, just read the headline and make a low effort comment. Regression to the mean I guess.
As an update to myself, the comments did eventually sort themselves out. I guess the initial "reaction" commenters and voters are just more interested in participating than in SNR. Good opportunity for me to finally start blocklisting users, and I'll probably block some of these large, reactive thread authors.
In the past I wrote a version of HN that uses modern CSS rather than tables that populates stuff from the API. There I built a little blocklist of my own that prunes a comment tree the moment it encounters a blocked user (inspired by posts from another HN user, arjie.)
I've been thinking of making a purely algorithmic filter for myself but at that point I might just ditch the fake HN interface and make something. I've been thinking of building atop Mastodon/ActivityPub clients.