*Sigh* As I said in my example, once you are allowed inside the Public Meeting Room (I.E. Public Forum) ... in other words, it's taken for granted the definition of public forum meaning that one must either be invited or openly join the forum to have a voice. I did not state in my example that people outside the Public Meeting Room were conversing with those inside.
I think David's point was that Jun, as the forum owner, gets to decide whether it's okay to tell people their aikido is ugly. There are plenty of places where saying "sorry, this is the internet" when the forum owner has expressed concern about the tone of the discussion is a good way to get banned. Jun has a lighter touch than that, but that doesn't mean it's okay or desirable to push the limits.