Because drama is not the place to go to to complain about one small self-contained thread. If he was posting his awful art elsewhere, or he made multiple equally bad threads, that's one thing. This is just a kid making stuff he thinks is funny, and it looks like some people are contributing and having fun so just step off and let them do their thing. This is just being petty.
For one, the drama board right on the index says, "Internet drama and interpersonal problems". This is on the internet, consider it a problem. There's the sole exception that the thread has to be about blockland. It is because it's about the forums.
Your single argument despite the questionable placement of this thread, is that, "It's awful art, it's unfunny, it's bad. He thinks it's funny and some people are contributing. So stop complaining". You've got to admit that this is riddled with fallacies, because of the fact that just because people are contributing, doesn't make the quality of the thread any less awful.
I don't get your argument.