I've been in communities that were very pleasant and open about a lot of things where the only rule was, quote, "don't be a dick". I've also been in communities, that despite extensive rules that would make make fellows from my law course cry in joy and fully oriented towards left/liberal, were cesspools of hatred.
I think in both cases it's more a matter of what the moderation will do with what they have. "You reap what you sow" probably applies in some way.
There must simply be a commitment to health and purpose of community.
On the other hand, with written rules it's also harder for moderation to abuse their rights.
Either way, there will always be this commitment, the community usually figures out what they need by themselves when the decision becomes necessary.
The appeals are rooted in norms, and the process is a dialog, kept recoverable, not a trial.
Explain to me how a set of rules isn't a formalized expression if the will of those who created them?
There is more to all of that, in particular, security and agency.
But, those details aside, norms operate much like rules, and are far more resonant, and community owned than rules alone are.
Finally, the organic and well distributed nature of norms tends to check varied and manipulative enforcement of rules. A primary example might be a flare up, vs nefarious intent to make noise and or cause grief.
Think family vs Roberts rules of order.
The problem is, rules are also a way for someone who was wronged to appeal. While it's a line that troublemakers want to thread to push boundaries, when rules are unwritten, communities often become a reflection of the will of the moderator rather than a community of diverse opinion. Codified rules are one of the steps we have to encourage diversity of thought, but of course there needs to be rule enforcement...