Earlier quoted context omitted.
surveillance is not a solution to the problem it merely suppresses it. Treating symptoms is never as useful as treating the underlying cause.
We're lacking the tools to deal with this problem. All we can do is try and contain it.
Like others have said the damage this is causing is mostly mental. The number of random (I mean that as in could happen to anyone not downplaying the significance of human life) deaths caused by terrorism is not so large.
However this does not mean we should tolerate people who refuse to play by the rules of society because of their personal beliefs (whatever they may be). Any countermeasures must be above board and transparently fair.