re: the intended lesson
Frantic bluster and hyperbole were characteristic of Iraq before they folded up, too. Heck, if you listened to them, they beat us. Totalitarian systems don't know any other way to deal with people.
As with Iraq, I am really wondering exactly how much of this nuclear weaponry stuff North Korea really has, and how much is the regime's terrified bullcrap.
On the other hand, you might be wondering how much of it is just more CIA exaggeration... ;)