I think much of what is being discussed here stems from the failure of many current Western governments to acknowledge some basic facts:
In a 'free society', most individuals have the potential to cause damage and/or loss of life on quite a large scale. The fact that they generally don't do so is not a reflection on the level of policing/security they are subject to but on their state of wellbeing, mental health and empathy for their fellow men.
Any sufficiently open society is vulnerable to terrorist attacks, that's a given. Where the choice lies is in how that society responds to this challenge: by removing freedoms from all its citizens in a desperate endeavour to stay in control or by trying to understand why attacks are taking place and attempting to remove the cause itself. One leads to the creation of a 'Fourth Reich' or USSR MkII, the other, hopefully, to a more enlightened and safe world to live in.
Which do you feel more threatened by in the UK/USA: the risk of being killed by terrorist action or the 2am knock on the door from the security services? Statistically, which is more likely to happen to you these days? If you think I'm being flippant, remember Guantanamo Bay for the USA and the police in the UK wanting to keep suspects imprisoned for 90 days or more without trial or charge...
Sorry about the rant - possibly slightly off-topic but I needed to get that off my chest!