"We had that war won until John Kerry and Hanoi Jane Fonda stuck their nose in it," Gardner said. "Hes a traitor."
That last bit is the real story here. Vets who still believe that Vietnam was a winnable war if not for public opinion turning against it, and who hate John Kerry for playing a role in turning that opinion.
Hate him enough to lie now, and lie repeatedly, on the record.
If I were any of these guys I would think about getting a good attorney, because "freedom of speech" does not extend to knowingly promulgating lies designed to injure the reputation of another person.