I must say that not all TSA folks are nasty or stupid. On the contrary, first type are probably in a minority.
But many of them do believe that they are protecting us, that leaves me wondering about the second type.
On one occasion, I was too tired to even feel upset about having to take my shoes off. So I did everything like a good boy. Emtied my pockets, took the shoes off. Put my watch, glasses and even my padge with a metal clip in a little bin. I didn't beep as I walked through the arch. Yet, I was taken aside for secondary screenig. My curioisty beckoned me to ask "why". The answer was "We can't be idle. We have to be cheking some one or the other at all times." Since they had just finished screening the last person who had beeped, they used me as a prop to look busy. So I said jokingly, "What do you guys do when there aren't any passengers going through? Wand each other?" He gave me cold blank stare, but I suppose my grin was too benign that he had to start laughing.
I am sure many screeners know they are just going through the motions of looking busy. SO my question is why? ofh why are we so stupid to put up with this circus?