An officer swears an oath to the constitution not the President. Americans don't recognize omnipotent leaders, we recognize the rule of law.
Because you said that you thought General MacArthur "should have gone ahead and bombed the crap out of North Korea" with nuclear weapons, in violation of the express orders of President Truman. If the Army can violate the orders of the elected President -- particularly with regard to the use of nuclear weapons -- then I don't know what you have, but it's certainly not any kind of Republic.
Civilians should run the country, Military Officers should run the wars
I don't disagree with that. But when you get a conflict between the two, the civie is always in charge. That always has to be the case, even when the civilian is wrong, or else you have chaos.
An officer swears an oath to the constitution not the President.
That's wrong no matter how many times you repeat it. Every officer has sworn to obey all lawful orders by the President.