Two lines of troops face one another. In a gentlemanly fashion, one line gets to shoot rifles first and kills a large number of those they face. Then the other line regroups and gets to shoot the first line. Eventually, many die on both sides and a sort of pause is put into effect. Much more humane: fewer deaths. Compare this to WWI on the Western Front, where owing to more powerful weapons each side destroyed a much larger number of the enemy, all without resulting in any change in territory controlled. It was in eastern Europe that a more exciting way of fighting occurred: massacres of civilians, execution of prisoners, etc.
In Response to: Jacob Shapiro on Modern, ‘Small’ Warfare