As someone who has done a fair share of work in airports (digital signage) and has been badged in a couple of term, I can say this from observation and from talking to people in the airports and the TSA, the issue is not the passengers, it's the workers. The passengers are checked to ridiculous measures, but if you work at an airport your protocols are entirely different. All the tarmac entrances and any "employee only" entrance isn't guarded by the TSA, but rather independent security companies hired by the airports themselves, so every airports strictness at these points are anywhere from stricter or far more lax, especially if you're a regular employee that they recognize. I have had to throw gear into the back of an electricians truck many many a time and driven it onto the tarmac without them opening or even swabbing the boxes. At that point I am less then 30ft away from a 767.
All this extra effort at the checkpoints is to keep up what most people here already know what it is. The illusion of absolute safety in a system where it can never be guaranteed 100%.