I think deep down a lot of people there realize the stupidity of what they are saying. But they also know any lapse or any deviation from the "rules" would put them back on the street or back to flipping burgers.
I had an interesting encounter with a TSA agent. He flagged my bag because I had 10 notebooks in there ( I took them with me to read over my notes over a couple of years back ). He thought it was strange. So I told him, yeah, it is programming stuff. He said he likes programming, and would like to do it again sometime, asked what languages a popular these days (he knew about C++ only). I told him to try Python for example.
At first I was annoyed at him for bothering me over stupid notebooks, it was ridiculous. But then felt kind of sorry. Here he is, thinking he wants to develop software, yet he has to flag down bags and look for shampoo bottles, notebooks, multi-tools sift through people's dirty laundry and so on.
If I really wanted to threaten someone, I think the metal pen in my bag would be more of a threat than a tiny multi-tool knife that would probably fold back and cut my own finger if I tried to use it as a weapon.