Governments going completely insane on their people are relatively common. Everyone thinks it will not happen to them, until it does. That's a much greater risk than rogue individuals. To double the big risk to half the small one is bad risk management.
I agree if you express it not in terms of probability of event (rouge individuals pop up every day somewhere) but expected damage. There is only so much one man can do today, so it's right to focus on big risks and not small ones. But technology tends to change things, and I fear that upcoming biotech (and possibly pure nanotech in more distant future) will drastically change the equation, giving unprecedented power to rouge individuals with ill intent. The question is, how can we defend from that; how can we minimize the amount of damage one person can do?
