Just pointing out that I've never seen an online community with such poor mental health.
I've seen quite a few but they're all incredibly similar to ResetERA.com's prominent members to where they have almost literally the exact same interests like Marvel films, ACAB, "you can't have ethical consumption under capitalism", yikes, oof, etc. The publicly self-proclaimed seriously detrimental mental health issues are abundant in them all.
I think a core component to them and mental health is that they're all strongly dishonest and they encourage dishonesty to the point of demanding it. The elites of ResetERA.com take it out on anyone who isn't playing "the game" by wanting them literally banished. People often say things like "I couldn't imagine posting in a community where you have to walk on eggshells" or whatever but I think that dramatically underplays the forces at work in these communities. That theory presupposes that people know better and are simply doing it to maintain their position in the group and while this is a factor I propose that the major factor is actually that everyone in the group willingly subscribes to it. They confuse performance for truth and so require that everyone continually perform rather than be truthful.
In essence, people don't speak up and effectively say "get over yourself, you're not that important" to those in the group not out of fear of being outcast but instead because they have willingly chosen to do the performance and there's too much danger (stay safe) in admitting that choice was wrong, that you shouldn't have performed rather than tell the truth. The endless dishonesty erodes both the sense of self and sense of community which
then leads to the necessity of clinging to the pretense of the "community" rather than be abandoned to your own frightening individuality.