How? Korea was a Japanese colony from 1901-1945.

Why would we not argue that the Korean War was an attempt by Koreans aligned with Japan to maintain their colony?

Because that would be false on its face. I'm sorry that you have no idea what you're talking about? The Korean war began when the communists invaded from the north, equipped and trained by the Soviets. It continued until the communists by then actually from China not North Korea, stopped trying.

At no point during the entire Korean War was there a Japanese colony anywhere on the Korean peninsula. Or, for that matter, anywhere on earth.

If you're arguing the South Korean government whose sovereignty the UN went to war to defend, was somehow "aligned" with their former occupier Japan which was itself then occupied by the US after its unconditional surrender to end WW2... sorry, you're just woefully ill informed.

There are dozens of good books on this topic.

Interesting, so what you're saying is after the Japanese lost their Korean colony, the country was split into two, then communist aggression from the North invaded the South which resulted in foreign powers stepping into defend the Southern half of the country.

Sounds pretty similar to France losing their Vietnamese colony, and the country being split into two, and then a foreign power coming in to defend the southern half of the country.

So it looks like we agree?

As far as I know the US backed the French and took over immediately as soon as they were kicked out. Though Korea and Japan were analogous, even though the US didn't actually support the Japanese occupation, it continued it.

I imagine the Koreans welcomed the US, that would be an important factor.