Those guards were from a reserve MP unit, not soldiers assigned to the rear from a line unit.

Also, there's more there than just the MPs. I highly suspect that there are some spooks (MI, CIA) involved that were somewhat behind this. Like 4Salt said, "softening them up."

I'm also very curious about what will happen when it goes to trial because, like Elvis said, humiliation isn't really against the Geneva Convention. But, humiliation is a relative and subjective term.

And don't be so sure Bush didn't know. There was a report submitted to Myers and Rummie in December. If Bush truly didn't know and he doesn't fire Rumsfeld, then there's a problem. I think Rumsfeld told him but they tried to keep it low key and hope it would blow over. That's completely understandable in my view. Hell, that's what I'd do. Stuff happens in war. Sometimes you just gotta hope it goes away before anyone finds out.