TSA Pat Down Alert

I know the TSA people are all really professionally trained to catch the bad guys before they get on a plane and cause havoc. So why do they have to put old ladies and others, who are obviously not a threat, through these intrusive body scans and pat downs? Because they are afraid to use profiling, so they profile everybody. The police use profiling every time they make a traffic stop. They find out who the driver is and if the car has been stolen, so they can find out who they're dealing with. Why can't the airlines do the same?