By which I mean, I'd chip in to calm him down. I'll buy him a gently used Toyota, tomorrow, if it means he will settle down. I'm not even kidding. I'd even take him at his word. Hell, set up a PayPal account, and make it legal, and I'll send him money every month that he doesn't harass his neighbors. I'm pretty sure I'm not the only one.
Hmm... We should crowdsource Un's Scotch fund. I'm only partially kidding.
I don't think they are harmless but I also don't think they are suicidal, this just happens to be the only leverage they are willing to use.
The minute they destroy a real city they are game ends and the rest of the world is going to actually do something. They LOSE negotiating power and are inviting in attack against them that will destroy the regeime.