Thats the part I never got either - I remember after 11/9 that I had wished America was British, because you guys reacted so sensible and wouldn't have gone so crazy. A country that can survive the Blitz isn't going to care about a couple of buildings.
Stupid lawmaking aside, I was really proud the day after the London bombings to see so many people commuting to work regardless. There were a fair few white faces and it was deathly silent but the place was still packed. You can blow up our trains and murder our citizens but life goes on.
I feel like they acted the way they did because they thought the public wanted to see some kind of action in response to the threat. It's as much the fault of the British public for being so ambivalent about politics that the government is left trying to guess what we want.
Perhaps if more people were to study modern history it would be a bigger issue. Outside of my immediate friendship group, most of the people I've talked about it don't seem to view it as an issue. If you don't explicitly value civil liberty then it seems like a fair exchange for the chance to catch a terrorist before they act. Not many people think it through further than that.