I think that there is a distinct statement being made to show that human beings have the capacity to being uncivilized. The fact that the sniper cares only for taking out his target that he can put off his hunger in the "excitement" for killing another and that he has no problem eliminating others in the pursuit of his mission reflects the uncivilized nature of the sniper and human beings in war. The condition of war is shown to be one in which the worst in what it means to be a human being is evoked. In the sniper lies the capacity for behavior that is far from civilized. When the sniper fails to care about his own wound in the drive to take the target out, one recognizes the capacity for uncivilized behavior that is brought out by modern war.
I tend to think that the story does show the capacity for civilized and honorable behavior does exist. As the sniper changes, this capacity is illuminated. While it is easy to make the claim that the sniper is uncivilized, it is also the sniper that recognizes his own culpability and feels regret over it. The sniper's change helps to bring out that human beings can be civilized even when the conditions around them seem to indicate otherwise:
The sniper looked at his enemy falling and he shuddered. The lust of battle died in him. He became bitten by remorse. The sweat stood out in beads on his forehead. Weakened by his wound and the long summer day of fasting and watching on the roof, he revolted from the sight of the shattered mass of his dead enemy. His teeth chattered, he began to gibber to himself, cursing the war, cursing himself, cursing everybody.
The fact that the sniper himself realizes the implications of his action and shows regret towards them holds out hope for the civility of human beings in a world where such lights are darkening with a rapid pace. The fact that the sniper recognizes himself to be his own brother's murderer is a part of the redemption that makes civilization possible in a world of uncivilized behavior that threatens to subsume it. The sniper's revelation and epiphany is a part of this process.