And as I have said in other posts, Security Theater is the entire point. The objective is to discourage the maniac from choosing an airplane for his nonsense, and going for a softer target, like a school, or mall, or something.
It sounds terrible, but you can kill 200 or more people in one blast on a plane, but even the most successful mass shooter had about 80 victims, and most only have a few, less than 10, often less than 5. That's horrible, but it's far better than hundreds.
Since 9/11, and the introduction of TSA and the enhanced security protocols, we haven't had a single successful hijacking in America, while we had hundreds before 9/11. That's success, and that's why TSA exists.
Would you rather get on a plane that has had no security scan of any passengers or baggage?