Protection from harm in a free society is a childish dream. People intent on causing harm will not be stopped without an absolute police state where every move is tracked. Locked cockpit doors and passengers who are willing to murder hijackers with their bare hands have pretty well eliminated the threat to airplanes. No need to spend tens of billions of dollars on groping children.
Besides, if a terrorist wanted to cause harm, they wouldn't even need to get past security. Just detonate a bomb in the security line waiting for the TSA checkpoint. What then? The pre-TSA, who screens people before they're allowed to get to the TSA checkpoint? And what happens when that vulnerabe point is attacked? The pre-TSA-pre-TSA who screens people before they're allowed enter the building to go through the pre-TSA checkpoint before they're allowed to go through the TSA checkpoint?
If you want to be safe, never leave your home.