Every warrior society has, for thousands of years, experienced a "purification ritual" to help returning combatants deal with their "blood guilt" and to reassure them that what they did in combat was "good." These rituals traditionally involve long periods while marching or sailing home, the cool-down, group therapy period.
The introduction of “conditioning” in modern army training, aircraft, technology & the individual replacement system that hampered bonding and ensured that soldiers often arrived and left as strangers, resulted in the denial of this purification ritual and millions of psychiatric casualties, hence the discovery of PTSD. Post Traumatic Stress Disorder.
It is often said that "All's fair in love and war," but is this a cultural conspiracy?