I think that’s a slight exaggeration, although I get what you’re saying. But I think it’s important to demonstrate to libs that I’m being consistent so I’ll explain what I mean.
I don’t think the communal decision making bodies that spun up in the wake of the Japanese evacuation were necessarily completely aligned with Kim or the communists in exile, it was virtually impossible to maintain a functioning domestic apparatus and what I’ve read makes it seem like these were mostly improvisational.
That said, I think in the long run you’re right, I see it as similar to Vietnam later: because US foreign policy was aligned with elements that were naturally unpopular to the population of the country (in Korea’s case, the Japanese and domestic collaborators) a democratic resolution of the question of what sort of government a united Korea would chose for itself was not going to be an acceptable outcome to the US.
But we don’t know what they would organically choose for themselves because that decision was foreclosed by US occupation. I suspect a popular referendum was the best possible outcome but I think it would probably look very different from the current DPRK, for understandable reasons.