The problem with such an idea is that there's a lot of room for abuse below what can be expressed in the form of rules, which means it can be difficult to moderate without appearing to censor or favor particular sides.
People can be abusive in subtle ways that enter a gray area of civility. For example, a discussion thread that devolves into a combative exchange about what a participant really meant by their comments, and whether that means they're a white supremacist, will eventually become exhausting and pointless, and everyone knows it, but what kind of rule can ban "exhausting and pointless" threads?
But any moderation that can't be enforced on technical terms will start making the enforcers seem subjective and biased. Reddit has a long record of subs abandoned in anger by a large cohort of users because they consider the mods to be unfairly biased, and it's not always the case. Conversely, forums can die if the "good" users think that not enough is being done to shut up problematic users.
I help run a private discussion board that's been active for ten years now. It's great, but it's had its own share of drama. The hardest problem we had was a person who simply incited trouble. He didn't break any rules. He was just a very difficult person, and we knew (through friends of his) that he had mental issues. In the interest of being fair and keeping to our terms of use, we let him stay. While there were people who openly argued that the community should have room for people like him, others complained and started leaving the site, just because of all the heated drama. This went on for years. After several incidents where it just became too much, we decided to ban him permanently. But it was a hard decision. We still have "problem users" who, purely by voicing unpopular opinions (from nationalist/fascist sympathies to belief in anti-vaxx or rejection of Western medicine), incite a lot of heated discussions. They're not breaking any rules, they're just loud and controversial.
I think a discussion board lives and dies by the trust its users put in the moderators.