North Korea might be a kind of troll.
Trolls annoy people. But they also entertain, and present no real threat.
Rather, they make people feel good. Because they make people think: "I'm so much better than that stupid troll".
Thus they perform a valuable service, by boosting public self-esteem.
And that service may be provided on an international scale, by troll countries like North Korea.
Is North Korea secretly backed and funded by the CIA?