This is tankie garbage. Syngman Rhee was certainly horrible. But he was not instated. He was voted in. He had a very long history of being in Korean politics. He was certainly given a boost by the Americans. But he was also given a boost by Kim refusing to participate in the elections.
And let us not pretend that the soviets and Chinese involved were just liberators. They had their own political games they were playing and boosted Kim just as much. The elections in the north were completely controlled by the soviets. And you gripe about the presence of American troops, but support the Chinese troops in the north.
The north didn't invade for fun. The north invaded because Kim thought he could have even more power and that the US would not intervene. He was wrong. He would have been completely removed had it not been for the Chinese.
Both sides had imperialistic outside support from corrupt governments. Both sides used totalitarianism to maintain control. One side is currently the most inhumane country on the planet and the other has a modern standard of living. To say the south was worse in a very short time period is ridiculous. In reality, due to the harsh restrictions and cult of personality in the north we do not even really know how bad the north was. The standard of living may have been better, but concerning totalitarian governments it is impossible to say.