While Spiff is yet to notice and jump on that, I'll try and correct this a bit.

They aren't even "security agents", they are merely screeners (also doubling up as airline revenue protection officers), meant to ensure that you are not carrying any "prohibited items" into the sterile area. The "job" they perform is essentially outsourced and is performed by external contractors in many airports across the world (and probably performed in a better fashion and a polite manner).