Except China is fed up with the DPRK too. Anyway. Kimmy had to deal with a coup attempt last november, so he's got to do the whole macho hollering thing his dad and grandad did, but even harder to show how tough he is. It's just a thing they do. The difference is that the South doesn't really play nice anymore-they've said recently that if the DPRK ever employs their nuclear weapons against them, they're going to plain wipe the North off the map, which is well within their military capabilities.