There is no way we could match them in numbers on the ground. Such a conflict would have inevitably led to us nuking them as a result. Which is probably the reason decision makers chose not to.
And maybe that's really the humanitarian failure. That USA didn't nuke China in 1950 or 1951. Would have solved a lot of problems for generations of people.
Nukes usually don't wipe out entire countries, especially tactical nukes.
I'm far from convinced that using nukes in the Korean War would've been a good move, but equating it with "kill[ing] them all" is completely dishonest. What's your goal in this debate, and is it served by dishonest rhetoric?
USA dropping nukes would have prevented the convention against using nukes in wars from being started. I think there's a pretty good chance we wouldn't have any civilization left by now if we went down that fork in history.
How is nuking Japan different from nuking Korea? Everybody agrees that forcing Japan to surrender with nukes was much better for everyone involved than a ground invasion.
Maybe the real humanitarian failure is that the US didn't nuke everybody and start over from the stone age. Can't any societal problems if no societies exist, right?
The US nearly lost the Korean war.
The US army was nearly overrun at least once.
The US airforce never achieved air superiority, and Soviet aircraft were better in most ways.
The only undisputed advantage the US had was nukes, which is why MacArthur wanted to use them tactically (!)