That might be what you'd expect, but what we actually see is that militaries have explicitly tracked status (rank), and strong enforcement of that status (orders), and it's been that way for at least as long as we have records. They also tend to have the death penalty for a wider variety of things, including for attempting to leave (deserting), for which there is a strong incentive that applies to everyone at once with a shared but varying strength.

Another interesting fact about warfare is that it makes tribalism a simple classification problem (my side/their side/neutral) with a high penalty for error; and wearing the wrong clothes (uniform), looking different (geographic origin), speaking differently (accent) or not recognizing culture references, are all strong indicators that someone is not on your side. Visibly trying to hard to match these criteria but failing would indicate a spy. Judging people on these things in daily life is bad today and probably wasn't ever much better, but in war they're proper Bayesian evidence of something important.

I also think that it's probably a bad idea to talk about "the ancestral environment" as though it doesn't include the most recent millenium. Some traits do evolve fast enough for selective pressures in recorded history to matter.