A quote from Kubrick about war films:
"One of the attractions of a war or crime story is that it provides an almost unique opportunity to contrast an individual or our contemporary society with a solid framework of accepted value, which the audience becomes fully aware of, and which can be used as a counterpoint to a human, individual, emotional situation. Further, war acts as a kind of hothouse for forced, quick breeding of attitudes and feelings. Attitudes crystallise and come out into the open. Conflict is natural, when it would in a less critical situation have to be introduced almost as a contrivance, and would thus appeared forced or, even worse, false."
From Paul Duncan's book Stanley Kubrick: Visual Poet