You have to look waaay back from before WWI, WWII, and the times between and after to understand how the Koreans were screwed over by everyone. The transfer of Korea from Japanese colonial rule and its split at the 38th parallel to USSR (N) and the US (S) all but guaranteed that Korea's many attempts at democratization would go nowhere. Keep in mind that under Japanese control, heavy industry was concentrate in the north and agriculture in the south. This helps explain one reason why there's not enough food to properly feed the people in the north today.
The US couldn't allow the Koreans a true democracy because they were afraid the people might decide to go with communism, so it seemed to be in everyone's interest to divide the country among the victors.
Anyway, not to hold the leaders of North Korea blameless, isn't it interesting to note that we've had our hands in the internal affairs of most of the countries that are out to get us??
"I wish I had documented more…" said nobody on their death bed, ever.