A sniper is no different than a line infantryman or a bomber pilot. All have assignments in combat and follow orders. In the case of a sniper his assignment is to kill individuals - specific individuals. Somehow people perceive that role as different than anonymous killing by dropping bombs. It's not.
You attached the "ignorant" word to this. How is that relevant? What is this soldier ignorant of? He does his job, follows his orders. That's what soldiers do.
War is a clash of wills. The protection of life, rights and Freedom is the only moral justification for engaging in war. Anything else, especially socialist goals, amounts to subjugation and killing to gain substantial control over the Free will of other persons against their wishes.
The fact that folks will attempt to do this has been recognized by various people from the foundation of history. The founding fathers knew it, that's why they created the U.S. Constitution to contain it's balance of powers and included the Bill of Rights.
If folks were unable to think, decide and accept responsibility for themselves and their acts, there would be no point to free will, rights or Freedom. The experts, the best and brightest folks with all answers, smart plans, vision and the most effective gd army of thugs would rule.