Um, unless you are at war with any of those countries, you go and kill someone, you are a murderer, plain and simple.
I agree. The cops are simply the enforcers of the law and a lot of times those cops themselves don't believe in the laws but they are forced to enforce them because they need the job to support their families.
Why does war change the situation? The Soldiers are just doing a job to support their families, like the cops.
I would say all of the above. But then again I don't believe in right and wrong. But there is no doubt that oppression takes (or took) place in all the above mentioned countries, and one certainly cannot blame anyone for defending themselves and their freedoms against the police of a Police State.