Stating the obvious
Much of human actions are concerned with very primitive instinct, namely fear.
Fear is a critical faculty for survival of organism. This instinct combined with capacity for abstract thinking makes man imagine and sometimes invent danger, other animals are too preoccupied with real dangers to imagine any. I think when somehow this above combination becomes controlled it gives rise to all kinds of phobias and paranoia.
Arising from fear is the strong need for reassurance. Humans have pursued this since time immemorial.
Much of rituals in religion exist because of this. This is not limited to religion, wars are waged, massacres committed because of fear, whether of few well placed individuals or masses. I have come to believe that much of global warming cult is a manifestation of the primal instinct.
There is not much one can do against such primitive force, for which even the most developed civilizations have limited as well as ineffective antidotes.
The most effective countermeasures are, availability of information, and capability and willingness to act on intelligence well before the problem attains dangerous dimensions.
It is in this, that any action against terrorism has to be judged. US was responsible for 9-11, but not by repressing middle east or Muslims, but by failing to decisively nip the growing network of Islamic terrorism in bud during last decade.
Similarly UK should be blamed for 7-11 because it ignored to address the problem of radicalism.
