Thing is, it IS easy to look on NK as the kid thowing his standard tantrum he always throws when he can't get his own way.
The difference this time is China, for the first time NK has been left totally on its own, with even China voting for sanctions against them for their behaviour. NK is used to throwing all these insults from behind China where they feel safe, and now they feel more vulnerable the rhetoric is getting even more insane.
The problem is, without the weight of China behind them NK looks somewhat.. silly.. for making all these threats and gestures, and I think they are aware of that, but it makes them even more angry.