It's backwards, the citizenry doesn't have to tolerate their government, the government must serve its citizenry.
You should ask yourself why the police should not be allowed to do this. And then if you do understand, you may perhaps realize why the GCHQ should not be allowed to carry out mass surveillance.
So which is it. Do you expect people to stay and fight perceived injustices, or leave? You can't have it both ways.
Its not about having anything to hide. Its about whether or not others can use your work against you. This happens far more often than real terrorism, and it ruins lives, industry, and culture when it happens.
Even setting aside crimes, there's plenty of things that happen in peoples' day-to-day lives that the government has absolutely no business even being aware of. It's not hard to imagine that they could collect vast troves of information on a person and then that information can get misused in any number of ways by rogue employees or by the government itself.
[1] http://www.amazon.com/Three-Felonies-Day-Target-Innocent/dp/...
I don't want to live on this planet any more.