> Somehow its only computers where people turn off their brains and argue that proactive measures need to be 100% effective at blocking all attacks no matter how high the cost.

I don't think I've ever seen anyone say they should be 100% effective. Even those physical locations follow some physical security practices. The difference is that computers can be attacked from literally anywhere in the world, and good luck finding the people who did it.

But even the best physical security principles really only deter polite criminals. The breach is just as impactful whether someone leaves a door unlocked, or if someone just observes the hour a janitor leaves at night and waits outside the door and clubs him before he can lock up. What difference does it make to those affected by the breach between those two situations?