The treatment of communist guerillas by the South Korean government was substantially more humane (and far less bloody) than the treatment of civil society by the military junta ruling North Korea up to and including the leadership of Kim Tu-bong, who was himself dissapeared by Kim Il Sung in 1949. The problem here is that the hard-left stalinist policies that were widespread in the 30s-50s (and imitated by Mao) required a
whole-scale attack on civil society:
* forced collectivization of agriculture
* attacks on schools, press, and bringing all instutions under the control of the party functionaries
* execution of monks, priests and missionaries and destruction of all religious organizations
* seizure of all private property.
Enforcing something like that requires a very bloody attack on the entire civil society:
"Concentration camps came into being in North Korea in the wake of the country's liberation from Japanese colonial rule at the end of World War II. Those persons considered "adversary class forces", such as landholders, Japanese collaborators, religious devotees and the families of people who migrated to the South, were rounded up and detained in large facilities. Additional camps were later established in the late 1950s and 60s in order to incarcerate the political victims of power struggles along with their families as well as overseas Koreans who migrated to the North. Later, the number of camps saw a marked increase with the cementing of the Kim Il Sung dictatorship and the Kim Jong-il succession."
source: https://en.wikipedia.org/wiki/List_of_concentration_and_inte...
You can argue that Stalinist dictorships destroying civil society are a good thing, but trying to claim that the US "invaded" South Korea with 300 troops is absurd.
> any improvement in those areas happened in South Korea and Taiwan rather recently, in the past thirty years or so.
There was no period of time in which North Korea was more free or respectful of human nature than the South, as evidenced by people continuing to flee to the South from the North, which is why the North had to build walls to keep people in.
It is because the government of the South did not launch a wholescale attack on human nature and provided more freedom than the North that it could evolve in directions that promoted greater individual liberty over time, whereas the North remained mired with famines, collectivization insanity, and repression.