As long as the misquote isn’t attributed to a specific member of the board. 
Seriously though, what legal action could someone take? What judge would see a case about altering a post on a messageboard?
Or was it just something where it was just too much of a hassle to deal with so a rule was created?
Once every five years or so I’ll have a work situation that leads to a disgruntled client telling me I’ll be hearing from their attorney. I always go overboard acting impressed, telling the person that I love courtroom drama and look forward to our upcoming tryst.
That’s as far as it’s ever gone. But I act like I’m taking it seriously. If the person backs down and “wants to be friends again” I explain that on advice of counsel I can have no further contact with them until the case has been adjudicated.
Basically, I treat it as a threat and I don’t like being threatened.
Well, let us say that person had announced his real, public name, and posted “Of course I hate Nazis” but someone changed that to “Of course, I am a Nazi.”- and then spread around the fact that the poster had admitted being a nazi. I can see where that might be litigated.