The repetition of the phrase "War is kind," as seen in Stephen Crane's poem "War is Kind," can be justified in two ways.
First, Crane is offering the reader an example of irony. The detail which Crane goes into, regarding war, contrasts the description of war being kind. Therefore, the use of the description of war being kind is meant to be ironic.
On another hand, Crane may be referring to the fact that war is kind because it allows those suffering from the battle of war to no longer suffer. For example, the maiden, the babe, and the mother are obviously worried about their loved ones fighting in war. Upon the death of their loved one, none of the aforementioned must worry any longer; their worries for their loved ones, in battle, dies with their soldiers: lovers, fathers, and sons. War has taken the soldiers lives, and with their lives their maidens, babes, and mothers no longer have to worry about them fighting. Fears are gone because war was kind.
The soldiers also have fears which war brings. The soldiers are beaten, bruised, and tired from the battles they fight.
Little souls who thirst for fight,
These men were born to drill and die.
The unexplained glory flies above them,
Great is the battle-god, great, and his kingdom.
It is in death where the soldiers finally find peace and rest; therefore, war is kind.