It’s interesting that you bring up wrongthink. Banning free speech would be something like out of 1984, but what we have is far more subtle and insidious. A system that shows you only what it wants you to see, while tricking you into thinking you’re seeing what you want to see.

Anyway, you can support free speech while hating this algorithm crap at the same time.

reddit is trivial, but why hackner news as well?

Anything that engages users?

Not GP, but I'd define it as anything which presents or orders/prioritizes user-generated content based on preferences not explicitly specified by the consuming user. That'd be something like "default to chronological friends-and-follows-only, with an option for friends-of-friends and an option for 'most liked within a time window', and (if Facebook is feeling magnanimous to a very few power users) a preference pane which allows controlling overrides to the chronological-ness like 'show posts up to X hours out of order if they have more than Y likes'". No recommendation/you-might-also-like system, but you can make the "accounts friended/followed by" button for a user's existing friends/follows as big as you like--so long as the list presented is only sortable only by name/follower count/date-added.

My hot take is that the courts should find that doing anything beyond that is a first-party editorial behavior and thus not immune to liability under section 230. You can operate social media, but if your content and recommendation sort algorithms aren't explicitly controllable by and legible to (that means no "you might like"; no direct payouts for content creators to be engaging on your platform; recommendations based on dumb sorts from people you already know or dumb sorts over keyword searches only) your users, you're liable.