Seems the imbeciles at the TSA have a few brain cells to put together amongst themselves after all. Maybe someone there was smart enough to realise, when pilots get to their place of work, I.E., the aircraft they have an array of weapons to choose from. Axe, etc., etc, tons of fuel and not to mention the aircraft itself.
Actually, no, this demonstrates the opposite: the TSA still doesn't know what it's doing.
For intrusive screening methods like this to work, they have to apply to everyone—otherwise the bad guys will simply impersonate whoever is exempt and avoid the screening that way. Or disgruntled formerly good guys will be "turned" by the bad guys.
If one follows the logic to which you allude above, then pilots should not be tested for drugs, since they could crash airplanes voluntarily while not intoxicated. The assumption that all pilots always have the noblest thoughts in mind is unfortunately a dangerous one. Just as doctors, lawyers, engineers, and persons of every other occupation can have sinister motives, so can pilots. And of course this applies to cabin crew, too.
However, since the TSA's Gestapo tactics really don't do anything to increase safety, anyway, exempting certain classes of people from them isn't going to make any practical difference.