This is the superior medium to be honest. Compare it to behemoth umbrella communities like 4chan or reddit and smaller places trying to be them; or to personally integrated sites like Facebook. People behave more or less civilly here where they have no reason to do so in the former places. It works that way on image boards because (barring a few exceptions) their near complete anonymity means you can do or say pretty much whatever you want as long as it's not literally illegal and you get banned without consequence, and places like reddit because while they do tend to moderate more aggressively you're still probably not going to talk to the same people more than once. That anonymity is valuable to discussion though, since people can't effectively employ tactics like shaming, social pressure, or intimidation to shut people down like happens in real life far more than actual reasoned debate, and social media is a complete wasteland because there's really no difference between what you say on Twitter and what you say in real life, except literal armies of strangers are just waiting to jump on you for it on top of people you personally know. The rare exceptions where people just make an account and use it without attaching any personal information to it still end up just shut out by the format of the site itself. Facebook style sites as an example are increasingly containing contact to just your friends and corporate accounts, and people are wary of interacting with obviously fake or anonymized accounts.
On a forum though, we have many of the same people around all the time and they can recognize each other by something more tangible than posting style. An actual community can form then, since people can get familiar with each other in a way that is impossible in less personal mediums. But, the only consequences of what you say on an internet forum are contained to the forum itself. The subset of people who can actually do something to you other than call you names is vanishingly small. The format has its own problems, but I can't say that it's been done better either.