Cause you can't ban a person just because you don't agree with him or if he is talking nonsense. Actions will only be taken if the person spams, making the forum unreadable...
On the contrary, it's his enemies who are spamming in 3in1, following up on every of his postings with disgusting pictures and taunts.
Can I appeal to his enemies? I know you guys have some bad blood with him in the past and I can appreciate the fact that you want to warn newbies not to be "taken in" by him. However, you don't have to do it on every of his postings. Telling everyone about his past, say, once a week should be sufficient (and for heaven's sake, stop putting up those disgusting pics. Write some good text will do). Then, it would be up to the forumers to decide if they want to continue engaging him.
By repeatedly spamming on every of his postings, some newbies may even think he is the victim and you guys are the real perpetrators !!
Think about it...