American veterans have a long tradition of making pilgrimages to their old battlefields. The journeys serve to memorialize the war and to honor those that lost their lives in battle. Vietnam veterans return to the Southeast Asian country for these reasons, too, but also because they have a need to make sense of a war that remains controversial.
"What makes Vietnam veterans different from World War II veterans who go back is that we lost in Vietnam," says Paulette Curtis, an anthropologist at the University of Notre Dame in South Bend, Ind., who has studied the phenomenon of returning vets. "Veterans that go back to Vietnam are reclaiming their place in history, both in a personal and national sense."
While the men who came home from World War II were celebrated as heroes, Vietnam veterans faced an American public that largely did not support the conflict in Southeast Asia. Added to this, American media coverage of Vietnam dropped off almost entirely after the fall of Saigon in 1975, so veterans had a hard time understanding how their role in the war contributed to the country's well-being.
http://www.csmonitor.com/USA/Society/2013/1110/Why-US-veterans-are-returning-to-Vietnam