Dividing Asian countries is standard US foreign policy MO.
There's a reason why there is a North vs South Korea, same reason why there was a North and South Vietnam, why there is still currently two Chinas, the Republic of China on Taiwan and the People's Republic on the Mainland - US antagonism to national liberation movements dominated by the Communists. Millions of people have died due to this policy; perhaps millions more to come
Indeed so, partition was only a fall back option if compliant government couldn't be installed, ala Marcos in the Philippines, Suharto in Indonesia etc.
US actually also wanted a United China, but didn't find it within themselves to indefinitely support Chiang Kai-shek (probably rightly from the US POV, Chiang was a China nationalist through and through and would not have been compliant to anyone) against the Reds, probably because it would have required using nuclear weapons on the mainland. Came close though, killing millions wasn't a problem, then or now
There's a reason why there is a North vs South Korea, same reason why there was a North and South Vietnam, why there is still currently two Chinas, the Republic of China on Taiwan and the People's Republic on the Mainland - US antagonism to national liberation movements dominated by the Communists. Millions of people have died due to this policy; perhaps millions more to come