i'd say it's less predatory for all users to have the same algorithm. maybe on HN, the userbase is small enough, and the articles generally focused enough, that it'd be less impactful were the algorithm somewhat divergent per user. but on other platforms, rabbitholes appear very quickly, and very inorganically. to be plain, i've liked a number of pro-palestine posts on instagram, and started getting very anti-semitic reels until i hit "not interested" a certain number of times. the algorithm is opaque, but also stupid, and motivated to aggravate me into commenting, scrolling more, etc., to view ads. i don't know if i have a way to categorize HN into "good" and ig/X/... into "bad", to be honest.

for what it's worth, discord doesn't really have a user algorithm to get people into certain servers, and yet people are readily radicalized on discord (especially to the far-right, in my experience), but obviously the way people interact on discord is different to social media.