This doesn't prove or disprove anything, but it shows how prisoner/guard relationships are fertile grounds for abuse.
The participants in the test were 'average Joes,' previously tested to make sure there were no aggressive tendencies. Good American kids. The test was to be for two weeks. It had to be stopped after only six days. Even the originator of the test found that he had come under the influence of power, imaginary power.
I can't understand why anyone could possibly doubt that atrocities are the norm, especially in military prisons.
If we don't stop this and face up to commiting atrocities, we are no better than the people who commited terrorism in New York and Washington, DC. I don't think the "we weren't as bad as they were" holds up in civilized society. An atrocity is an atrocity, regardless of its size.
The Stanford Prison Experiment
http://www.prisonexp.org/slide-1.htm