Via James Fallows. Simply put, our military occupation of Afghanistan—the police state we've imposed there—has limits on the indignities they'll inflict on the public:
A US Army staff sergeant, now serving in Afghanistan, writes about the new enhanced pat-down procedure from the TSA. Summary of his very powerful message: to avoid giving gross offense to the Afghan public, and to prevent the appearance of an uncontrolled security state, the US military forbids use on Afghan civilians of the very practices the TSA is now making routine for civilian travelers at US airports.
Everything about security involves a balance. "Perfect" security would mean complete controls on freedom, elimination of privacy, etc. Someone who is now exposed to real, daily danger in Afghanistan because of decisions about the proper balance argues that we need to be braver society-wide.
The soldier's note is worth reading.