And on the opposite side of the stupid-examples spectrum: any tech company that hasn't had a computer security breach should fire their security team. All they're doing is spending a lot of money to make their developer's lives a lot harder.
Anyone with clean floors should fire their janitors.
Etc...
Those don't mean every security spend is worthwhile and justified; but Simpsons quotes also don't mean that no security spend has any effect.
Do you believe there aren’t people who wish to use air travel for nefarious purposes?
Do you believe that none of those people are factoring in the presence of identity checks, x-rays, backscatters, bomb dogs, and metal detectors into their risk/reward calculation or the techniques by which they’d commit nefarious acts?
They're probably factoring in strengthened cockpit doors and passengers' willingness to fight back, because those actually work. The rest is security theater.
“By your logic I could claim that this rock keeps tigers away.”
“Oh, how does it work?”
“It doesn’t work.”
“Uh-huh.”
“It’s just a stupid rock.”
“Uh-huh.”
“But I don’t see any tigers around, do you?”
“Lisa, I want to buy your rock.”