[icegreentea]

Well, there are a few ways to parse 'should', and they really all boil down to what the hell NK even wants to do.

If they want to stop as many people from seeing the film as possible, then they should have done nothing. If they wanted to send a message that NK has the technical abilities to fuck up American (/Western) businesses, then they did the 'right' thing. If they wanted to score a less aggressive propaganda win, then they probably should have incorporated it into their next round of talks or something.