Why do you think the author chose not to give the main character a name?

I think the sniper is meant to be symbolic of all soldiers. Throughout the story, the Sniper remains a somewhat mysterious, one-dimensional character. The narrative reveals little of his feelings about what is happening around him, nor does it even share his reaction to the knowledge that he has become his brother's murderer. Instead, the story directs the Sniper's actions and thoughts to the battle. The Sniper's only identity is that of a solider.