Privacy was a luxury we had, while we could bribe the better angels of our nature with the surplus of the past and while technology was something, that did not scale.
Now a terrorist could take a army of tanks while besieging a city. All the other justifications for a Panopticon are flimsy, but the fact that technology - our savior from savagery, has turned around and bit the hand it was supposed to feed, justifies the thing.