I looked at the thread and three types of unrelated content I see:
1. schizo rambling in all caps with images;
2. political messages;
3. deranged rambling implying murder and such.
The more deranged messages are uploaded via Tor. I do not suggest disabling Tor since accessing from certain states that enforces censorship (such as Russia, the UK and in the near future EU countries) might be only possible or wise via Tor.
My suggestion is: mostly live with it, ignore it.
We can't translate and read every post so if board staff (BO/BV) sees something that encourages violence please delete it. The rest: don't bother.

I don't think there is inherent problem with unrelated content. And I know most of the stuff is posted to keep moderators busy, take time away from them. So the users should be patient. Yes, trolls who try to rob moderators their time can pretend to be impatient users.
Such is the conundrum of anonymous imageboards.