To be honest, as pathological a bunch of fruitballs as the family may be, this probably isn't the doing of Kim Jong Un any more than previous actions were the actions of Kim Jong Il, give them shiny baubles to look at and it'll keep them quiet for hours. No, the problem in North Korea, I feel, is the military itself. I think that Kim Il Sung had the military firmly in his grasp, but since that point, the descendents of that family have become little more than puppets for a military junta.
THAT is the situation North Korea faces, the only way the military can justify its huge power and influence is to convince the rest of the country that they live permanently under threat of invasion and war, if things are going to get even tougher, then much better to create a spectre of military intervention and blame it on those 'damn foreigners'.