During the Cold War we needed a presence in the area to stymie China and the USSR. Technology allows us to protect our interests from our own territory so . . . I'm sick of our humanitarian, good-will efforts being attacked.
I say we skip town and let the South Koreans learn first-hand that it is THEY who need us and not vice-versa.
My guess is the silent majority of South Koreans who appreciate our presence and know it's only our 40,000 troops that's keeping North Korea from annexing them will finally speak up and put a halt to all this US-bashing.
In any event, the world has changed and we don't need to have a military presence where we're not wanted nor respected.