I first started using the Internet in 1999, I've been a member of a number of forums some of which are still going, some of which have went under, some of which I have stopped going to for a number of reasons.
I'm a moderator at 2, in addition I also go to four other forums regularly and a few others semi regularly. The one rule that is universal. No two forums are the same, that article is painting a really broad picture of all forums. Sure, forums with no moderation can get heated, but it depends on the maturity of the members. GOG is unmoderated as far as I see but we're all fairly civil. One of the ones I'm a mod at has a number of rules that have evolved through the years (I've been a member there since 1999) largely through necessity, but even then, people don't get banned just 'because we don't like your face', you really have to do something pretty bad to get banned.
Really it all depends on the community, some can be elitist if you haven't got a certain postcount, or didn't join before a certain date, but thats the minority in my experience.