There was a time when the nations dealt severely when either ONE of the FOUR criterion of the Law of War was broken. Shedding the uniform violates this.
Because we have become so soft, we’ve opened Pandora’s box, and now have little moral authority to reel it back in. I speak in general terms that includes Western governments, starting with the Boer Wars.
So yes, they deserved to be killed. If members of a state or non-state actor breaks the rules, they should be hanged. Period.
Otherwise, war gets really nasty. 9/11 was never properly dealt with.
Who doesn’t deserve to be killed?