So yes, it's a hackneyed, hoary cliche, the amoral, maurading, kid-next-door-turned-trained-killer image is. But did you know this slander goes back even further than Vietnam? Getta loada:
During a period when veterans were big news, every time an ex-soldier got himself in a jam the fact that he was a vet was pointed out in the headline. An ordinary killing or assault seldom rated the front page, but if it involved a jealous veteran or battle-fatigue case, it could be sure of a prominent play. The newspapers that did this pointed out that it was good journalism; people were interested in veterans and everybody likes to know personality angles on people who do spectacular things. But the sad fact was that such headlines gave added impetus to the rumor that always appears in every country after a war--that the returning soldiers are trained in killing and assault and are potential menaces to society.
Police records show that World War II veterans committed no more and no fewer crimes in proportion to their numbers than the rest of the citizenry, and after a while most reputable newspapers stopped headlining veterans every time they got into trouble. Of course, journals that have always been noted for morbid and spectacular reporting, and that keep more of an eye on quick circulation than accuracy and fairness, still continue the odious practice of saying "CRAZED VET RUNS AMOK" when some character with a load of gin under his belt breaks a bar mirror.
-- Bill Mauldin, Back Home, 1947
Yes, we still have those kinds of journals today; they've always been around, doing their bottom-feeding thing. They just didn't always used to be The New York Times.