In the story "The Sniper," what does O'Flaherty want us to think about war?

When the story opens, the sniper is described as a seasoned soldier. He has become used to killing. He has the "cold, gleam of the fanatic" and has "the eyes of a man who is used to looking at death." An old woman on the street informs the enemy of the sniper's position. He has no choice but to kill the woman and the man in the turret. This is the cold reality of war. The sentiment presented here is "kill or be killed." It is primitive, barbaric, and inhumane. That is what is being communicated about war in this story.
O'Flaherty adds another morbid aspect to this story. The sniper is inevitably forced to kill his own brother. This is the tragic irony of the story and the grim irony of civil wars. They are conflicts of brother against brother. O'Flaherty does not go into the causes of the war and nor does he claim if one side is more justified than the other. Although the "sniper" is the main character, and although the reader might root for him, there is no sense that he is morally superior to his enemies. O'Flaherty also gives no indication that the enemies are morally superior. The author just presents the grim realities of war. Leaving the politics out of it, O'Flaherty just gives the reader the violence of war and the psychological impact war has on a soldier.