Let's squash this meme. Kerry's testimony was in 1971. By that time it was well established that atrocities had been committed:
Bertrand Russell's International War Crimes Tribunal had its first session in May of 1967.
Johnathon Schell's account of the destruction of the village of Ben Suc was published in 1998.
A soldier was quoted as saying "we had to destroy the village to save it" in 1968.
The photograph of General Ngoc Loan shooting a prisoner in the head was printed in 1998.
The My Lai massacre was reported in 1969.
Operation Phoenix to assasinate suspected Viet Cong was first reported in 1970.
Don Luce, with the help of Sen. Tom Harken, exposed the existance of "Tiger Cages", in which Vietnamese pacifists were imprisoned.
It was well known, long before the Winter Soldier investigation, that attrocities had been committed. What Kerry argued was that the attrocities were due to government policies, and that the policy makers should be held accountable.
It is well known now, that crimes have been committed against Iraqi prisoners. Those crimes were committed because of the policies of the Bush administration, and the policy-makers--all the way up to the policy-maker-in-chief--must be held accountable.