Maybe difference is majority of Vietnam actually hated US, even south Vietnam side because of atrocities (Zippo raids, Agent Orange, etc).
On the southern side of Korea, normal people hate communists (asians also just hate each other a lot and rhe North was backed by China) and actively sought US help + didn’t commit as much atrocities so good support and outcome for everyone.
Maybe difference is majority of Vietnam actually hated US, even south Vietnam side because of atrocities (Zippo raids, Agent Orange, etc).
On the southern side of Korea, normal people hate communists (asians also just hate each other a lot and rhe North was backed by China) and actively sought US help + didn’t commit as much atrocities so good support and outcome for everyone.