it is often possible to cripple or deny outright the enemy's war fighting capablity without directly klling a single person.
tactics like capturing and destroying oil wells helped in the (extremely deadly) countercampaign against the Axis, starvng the Axis of its ability to make war, in world war 2.
such tactics will likely starve the Allies in the coming war.
constructively all wars in the last 150 years have been energy wars.