The facebook/meta algo might be same for all users, but it had different inputs for each user.

HN, on the other hand, everyone has the same front page. If I like a post I can favorite it to 'bookmark' it, but HN won't modify my front page based on what I favorite, whereas facebook will.

I think the GP's argument is, when it comes to social media, "one size fits all" might be less addictive than "custom made" :)