Moderation isn't only about removing bad content, it's about removing content that's not necessarily bad but is unwanted. /r/gaming and /r/games are entirely different subreddits, with different content focuses and different communities because of their moderation. If I really wanted junk food content consumption I can go to /r/gaming. If I want to see news about video games I can go to /r/games. How do you accomplish that with client side filtering? /r/games has Indie Sunday where developers can post their own games on Sunday without competition from news about the massive AAA games everyone's already heard of. How do you accomplish that with client side filtering?
Good point. The majority of my Usenet memories revolve around meta discussions. What is and what is not supposed to be posted. Mid 2000s and people still had flamewars about whether a four line signature was to heavy.
Most meta discussions (beyond the basic etiquette and moderation, which were mostly worked out in the 1980s already) don't have objective answers, just subjective preferences. The solution is to keep aggressively iterating on splitting subreddits/communities/categories of users, until quality interaction is maximized. Obvious example: one category of user wants to discuss politics via memes, another category wants to discuss in long-form essays, another in threaded discussions, Canadians want to discuss Canadian politics without being flooded with US stuff, and plenty of others not at all i.e. they want any political posts off-topic and banned. The obvious way to keep all these groups maximally happy is to split into different groups.
Corporate/algorithmic moderation is almost entirely about removing "bad" content. You're talking about community moderation, which works exactly the same in decentralized systems.
