This is ridiculous. I believe that the North Koreans are being bribed by the American defense corporations, so that the latter group could benefit from increased sales. This is the whole chain:
1. US Corporations pay their bribes to the fat boy
2. Fat boy warns Japan and South Korea that he will attack them using missiles.
3. Japan and South Korea purchases missile defense systems from American corporations such as Raytheon.
4. More profit and revenue for Raytheon.
5. Increased tax revenue for the US treasury, and more local jobs created.
Who knows? I really cant say that one either even if you have a good logical thinking there is still a lot of wholes in it. They might increase their profit on the sales part but there are also some part of their economy that would surely goes down which i think US already knows