One thing in particular that should be pointed out is that the helmets themselves don't actually give you the power to defy, it merely enables you to defy with the powers you already have.
And the fact that every person is already fully capable of such wanton violence, well, there's a reason we see Makishima holding Heart of Darkness.
So when the
Panopticon falls, you just have to ask yourself whether what we're seeing is the truth nature of man, or simply the enabled darkness within him.