Anyhow, IIRC the forum rarely gets involved in such matters, good luck with your attempt to change the policies on that.
If a thread has gone horribly off topic or if there is an excessive amount of trolling and no legitimate discussion is taking place in the thread then the moderators may lock a thread.
You could also say that thread is a low/no value thread (it is probably
close to it), and as a result it should be locked.