I agree that they maybe could have different priorities (Although neither of the two of us actually know about the actual situation within the DPR), and I would support a more traditional marxist leninist interpretation of how to govern. But the reason for the songun (“Military first”) policy is pretty obvious when you look at the situation in Korea. They are under constant threat of invasion and bombing and the americans killed a fourth of their population within living memory (Albeit an old living memory). They are literally constantly threatened. And further any attempt by them to engage with the outside world is stimied and sabotaged by western powers.