I've read -- and this may be pure anecdote -- that false claims about how the American forces were treating prisoners of war may have contributed to that.
I guess the value system can be more important here. They had an order and they did what they were ordered.
Look at http://history1900s.about.com/od/worldwarii/a/soldiersurr_2.htm - the soldier surrendered immediately after receiving the order to do so read by his cmmander, but ignored all evidence of Japanese defeat before that.
I'm looking for historical examples of "flinching away," so I can illustrate the concept to others and talk about motivated cognition and leaving a line of retreat and so on.
The ideal example would be one of motivated skepticism with grave consequences. Like, a military commander who shied away from believing certain reports because they implied something huge and scary was about to happen, and then the huge and scary thing happened and caused great damage. Something like that.
What examples can you think of?