When forced to confront contradictions, we humans can come up with some of the most creative, roundabout stories to explain them away. So, as you see, all that is needed is a believable conclusion, and our minds do the rest.
This is why we obediently put up with actions that are patently ridiculous, like subjecting ourselves to fondling by the TSA. We accept the conclusion that it is for our own protection and work backward by filling in the justifications.
A more accurate narrative is that any terrorist with the most basic intelligence will know the security procedures and find a way to circumvent or avoid them. More importantly, total security is an illusion: it would require ever-increasing intrusions into our private affairs by people who could become, in real terms, much more of a threat than terrorists.