> How exactly do you want them to justify. Your demand is too vague to be even considered. How do you propose, they should advertise every thwarted terrorist attack, without alerting the other terrorists?
How about they stop doing it and if the level of terrorism remains in the "still kills fewer people than bathtubs" range, we realize we didn't need it.
> All security is plain unproductive overhead, which is compulsory in the presence of adversary.
All security is compulsory? Madness.
Security is risk management. All government activity is risk. You spend a dollar on surveillance technology instead of scientific research that would have led to safer products or life saving medicine and people die. You take a dollar from the taxpayer who now can't afford those products or medicine and people die. Government waste kills more people than terrorism. To say nothing of the people bad governments kill much more directly.
> You're basically saying, "don't trust the govt" and that is the recipe for total anarchy
Only if by anarchy you mean democracy.
