Here's the overview of this guy's book subject on the claims of Vietnam vets being spat on:
~snip~
Although Nexis overflows with references to protesters gobbing on Vietnam vets, and Bob Greene's 1989 book Homecoming: When the Soldiers Returned From Vietnam counts 63 examples of protester spitting, Jerry Lembcke argues that the story is bunk in his 1998 book The Spitting Image: Myth, Memory, and the Legacy of Vietnam (click here to buy it). Lembcke, a professor of sociology at Holy Cross and a Vietnam vet, investigated hundreds of news accounts of antiwar activists spitting on vets. But every time he pushed for more evidence or corroboration from a witness, the story collapsed--the actual person who was spat on turned out to be a friend of a friend. Or somebody's uncle. He writes that he never met anybody who convinced him that any such clash took place.
While Lembcke doesn't prove that nobody ever expectorated on a serviceman--you can't prove a negative, after all--he reduces the claim to an urban myth.
~snip~
Lembcke uncovered a whole lot of spitting from the war years, but the published accounts always put the antiwar protester on the receiving side of a blast from a pro-Vietnam counterprotester. Surely, he contends, the news pages would have given equal treatment to a story about serviceman getting the treatment. Then why no stories in the newspaper morgues, he asks?
~snip~
The myth persists because: 1) Those who didn't go to Vietnam--that being most of us--don't dare contradict the "experience" of those who did; 2) the story helps maintain the perfect sense of shame many of us feel about the way we ignored our Vietvets; 3) the press keeps the story in play by uncritically repeating it, as the Times and U.S. News did; and 4) because any fool with 33 cents and the gumption to repeat the myth in his letter to the editor can keep it in circulation. Most recent mentions of the spitting protester in Nexis are of this variety.
~snip~
http://www.slate.com/id/1005224/