What DPRK is doing when it builds nukes and demonstrates its rocketry capabilities is a deterrence. What the US does when it nukes Japanese citizens, takes over the Japanese imperial colony of Korea, drops more bombs on the DPRK than almost any country in the history of war, and then flies a nuclear-capable plane to that colony from the other side of the world is not a deterrent - it’s force projection, a threat, and a reminder that it is still violently in occupation of Korea.