Even a good war, even The Good War, is still a war, and it breaks and shatters people, physically and mentally. PTSD was not invented in Vietnam; Achilles seems to have suffered it. But societies have had trouble dealing with it as an illness and a trauma rather than a moral failing, from the British in World War I, to George Patton haranguing and physically attacking soldiers in World War II:
Patton was shaking with anger…”Your nerves, Hell, you are just a goddamned coward, you yellow son of a bitch. Shut up that goddamned crying. I won’t have these brave men here who have been shot seeing a yellow bastard sitting here crying…You’re a disgrace to the Army and you’re going back to the front to fight, although that’s too good for you. You ought to be lined up against a wall and shot. In fact, I ought to shoot you myself right now, God damn you!” Patton then pulled his pistol from its holster and waved it in front of the terrified soldier’s face.
After World War II, the PTSD was airbrushed out, perhaps so as not to complicate the victory that had been won over Germany and Japan. This led to the Army suppressing its own work, notably a documentary by John Huston, filmed in 1946:
The Army was so frightened that the film would hurt recruitment that when Huston tried to screen it for his friends at the Museum of Modern Art in New York City, a couple of military police came and seized it, supposedly on the pretense that the film would violate the privacy of the vets involved. The War Department claimed the releases signed by the men had been lost, but the Army never attempted to get new ones.
And so the film effectively remained out of circulation until now (there was a version released in 1980 that was, apparently, almost inaudible). The US still does not deal with PTSD nearly as effectively as it might, something critically important after a decade of war, but there is perhaps now some recognition that the country owes responsibility to those broken in service of its goals.
 Carlo D’Este, Patton: A Genius for War, (New York: HarperCollins Publishers, 1995), 534.