Black Hawk Down makes that point without preachment, in precise and pitiless imagery. And for that reason alone it takes its place on the very short list of the unforgettable movies about war and its ineradicable and immeasurable costs. Bingo.
Another excellent movie by Kurosawa. What's special about it is probably the Western movie's characteristics : the setting stage would have been fine for a Spaghetti movie, there are two clans fighting in the road, a corrupted sheriff, and even a gun. Not my favorite though.