Should we have fought harder in the Korean War?

[GUBU]

This is an idea that I've been thinking about more and more and it's a hard one for me to come to grips with since I generally have considered myself a pacifistic/non-interventionist.

Most people are aware of the totally messed up state of North Korea, where people live in a starvation/slave state, everyone worships the Kims as though they were living Gods, and there are literally concentration camps where generations of people are born and die. Comparatively South Korea is a well off democracy that enjoys the relative freedoms of the first world. My question is: should we have fought harder and longer in the Korean war and made all of Korea more like South Korea? A lot of times wars like Vietnam and Korea are portrayed as a complete waste of American lives, but when you consider that generations of people in North Korea are living in a brainwashed slave state and we helped save generations of South Koreans from living under the same slave state, it's hard to say that the lives weren't spent in a greater moral good and wouldn't it be an even greater moral good if we had stayed longer and liberated all of Korea for the future?

Keep in mind these are not rhetorical questions, I'm really not sure.

You do realise that for most of the period since the Korean War, South Korea existed in a dictatorship only slightly less brutal than the one to the North at that time? Until at least in the 1980's life wasn't all that spiffy in the South.