Are you suggesting this soldier was following orders? Otherwise your critique of the analogy is misplaced.That's not a good analogy. Everybody in the military (certainly in a "boots on the ground" role, which is what the OP seems to have done) goes through an intensive basic training program which is meant to alter their behaviour, with regard to things like unquestioning acceptance of the chain of command, overcoming their natural reluctance to kill, etc. Clearly this process is more effective for some people than others.
It doesn't seem very surprising to me that some people will continue with that mindset when they are back in civilian life, even if it isn't entirely appropriate.
Team members at a pizza store may also go through an induction process that is meant to change their behaviour of course, but the two sets of objectives are hardly comparable.
Either way, it is beyond illogical to blame everyone who served for the actions of a rogue.