True -- and I think most of us can at least understand why VTFW took steps to ban that particular commenter. But please let's not confuse blogs (where only the bloggers get to start 'threads') with online communities.
I don't think there is a sharp distinction between blogs and other online communities. Many of the blogs I read have a regular group of readers who have gotten to know each other via the comments. And while the blogger is the only one who can start a new blog entry, the comment threads can wander quite a bit (and are often the most interesting part of the blog). Also, many online communities have official moderators who can step in to nuke whole threads as well as individual comments, so even though anyone can start a new thread, they are not in total control of it. So the distinction between the two is more a matter of degree than an absolute difference.