These doors very effectively mean that control of the plane would be put into the hands of the cabin crew, but magnifies the cost of a rogue operator -- I am certain the risks were evaluated and the challenge of a determined suicidal pilot was ruled outside scope. And yes, there are emergency override codes, but there are also time override-overrides from within the cabin. Even if the protocol where two members of st…
Or to put it in a more general way: is security theatre now costing lives?
As is the way of things, the current manifestations of asymmetric warfare can muddy up the discussion with modern-day politics, so please allow me to remind you that science fiction authors have been predicting the rise of it since at least the 1980s, just due to the ever-rising destructive power any one individual can wield. Who or what cause happens to pick it up is an accident of history, but you can be guaranteed someone will try. This is an incentive structure that those of us on the side of civilization are going to be doing continuous battle with for a long time.