Most likely because, in the grand scheme of things, he's completely harmless. The moderators only seem to intervene when there's explicit rule breaches. Much like in a court of law, intent has to be proven and the threads themselves are worded vaguely enough to get by without punishment. As for those who have recognised certain patterns? They're free to avoid responding altogether in favour of keeping more engaging threads active instead.
Though I won't hold my breath, since many of the same people pop up in every thread to give the exact same reaction each time. It's hard not to think they secretly enjoy the 'drama'.