When in the history of the world has a serial human right abuser, dictator, fascist sob ever listened to reason and talk? All you do when you give these types of characters more is you make them stronger so when they decide to go on the offensive they have more weapons.
Now, a reasonable leader you can talk to, you can reason with, and it's often in your interests to do so. In the case of people like this nut in N Korea, no way you get through with words alone. That's my guess at least. Maybe you try, but after all of this time it's clear what N Korea is and more importantly is not.
