The US creates enemies, now certainly I'm not saying Kim Jong-Un is a saint or anything, but we can't overlook how the US has intervened in countries around the world, and North Korea is a good target for them, since they are a country that won't give in to their demands, totalitary state (like they didn't influence Latin America for the military to take over in several places) plus being an enemy of South Korea which is probably the biggest ally east-wise, so it's not crazy there's an agenda against them in particular.