Intention matters. It boils down to that, and there is a lot of nuance in being drafted to a war. For example, no guarantee of experiencing combat. And, some individuals need to undergo military experience to grow and evolve as human beings. More about intentions: It is easy to look from an earthly perspective at the situations of our lives and our reactions to these events by us. But Gods do not judge based on a superficial level. When they judge, they take everything into consideration, and that means everything you can think of and more. So when a man kills another, as the trajectory has already been set, it must happen. It comes down to the cosmic dance unfolding.
That is justice. Unfortunately, in the modern world, justice has been perverted to great lengths.
For the questions about war, I would refer you to the Bhagavad Gita, where Sri Krishna(incarnation of Vishnu/Zeus) meets with Arjuna on the battlefield and counsels him on the nature of life and death. Arjuna struggles with the duty of killing his enemies in war, even though they're evil.
