"And I SERIOUSLY doubt a LARGE percentage were "random people picked up on the streets" I mean really, what would be the motivation?"
This is extremely well documented.
Raids on civilians are conducted by kids with no training in investigation or police backgrounds. There's at least one verbatim report of a raid on an empty house. When the neighbor came out to find out what was going on, he was taken.
And of course, the prison guards are not trained, either. As an officer recently said: you tell a 19-year-old clerk that he's now a prison guard and his task is to keep a prisoner awake, he will find a creative way to do so.'
I know some Cons here find it impossible to believe almost any source other than Limbaugh, so I dug up the most conservative report I could find in 40 seconds of searching:
http://www.cpt.org/iraq/detainee_summary_report.htm