I don’t think that is the only possible outcome. Where moderation is done well lot of people, in fact most people, simply don’t notice it. They just have a pleasant time with other pleasant people. So no, “everyone whining“ is not the best possible outcome. “Most people having a good time, a minority whining” is the best possible outcome. And of course it takes hard work, and maybe even a little bit of luck with the initial conditions.
I'm part of two such communities that each have tens of thousands of active members, and have both been online for at least 15 years.
Generalizations are rarely accurate.
For example, politically charged discourse is suppressed. That's going to result in a higher level of civility, but now you have a large community of people with an impaired ability to affect the political process.
Unfortunately, people who are horrible to other people and/or spaces generally refuse to accept this, and therefore either need more specific examples of what being horrible entails to compare their behaviours against - leading to proliferation of edges, epicycles and rule-gaming - or you have a codicil along the lines of "the decision of what is horrible is up to the moderator and is final", leading to, at best, everyone whining about how unfair, arbitrary and partial the policy is now they can't be horrible to each other any more, all at once.