It wasn’t ‘North Korea’s’ temper tantrum. It was Kim being Kim. He’s mental. Absolutely certifiable.
There is also the problem of the brainwashed, starved, ignorant, backward people the Kim's have cultivated for the last half a century. Facts mean nothing to a people so backward they insist after watching a surgical procedure by medical doctors that Dear Leader healed the patient in question. I don't envy the government of South Korea. The entire population of North Korea is mental.