since he was told that only "the enemy" would be in the village, his honest belief that there were no innocent civilians in the village exonerates him of criminal responsibility for their deaths; and, finally, that his actions were in the heat of passion caused by reasonable provocation.
Although ordered by Calley to shoot, Private First Class James J. Dursi refused to join in the killings, and Specialist Four Robert E. Maples refused to give his machine gun to Calley for use in the killings
And Meadlo (the only one proven to participate) did not agree to testify against Calley until he was given immunity.
"I was just following orders" does not apply to the Calley case.
But it did apply to the Abu Ghraib case, where Soldiers were "following orders" from Intelligence officers. Did their defense work?