For decades North Korea has committed crimes against humanity similar to Nazi Germany in World War 2 and prior.
Kim-Jung-Um is no less than a tyrant. He sends those who disagree with his policies and ways of thinking to concentration camps and labor camps, showing no remorse. Those sent to such camps are more than likely to be executed, tortured or left in those camps for generations; including the children who have done nothing wrong.
While it is difficult to physically stop these atrocities, diplomacy can be conducted peacefully with North Korea in effort to build a relationship and hopefully calm down a country that seeks to harm Americans all over the globe.
This can also give further security to American troops stationed in South Korea at the border with North Korea.