The biggest reason to oppose agencies like the NSA spying on isn’t privacy, it’s innovation.
Put yourselves in the shoes of an inventor or a company contemplating investments in a technological breakthough. How would you behave knowing everything you transmit electronically can be monitored or stolen? First, you would be less likely to invest. Second, your progress would be slowed (perhaps drastically) because of precautions to protect sensitive information.
What if a US company unveiled a similar project just as you were about to present yours? It might be just a coincidence but what would you believe? Would you keep inventing?
There are no indications US spying is being used to pass corporate secrets to US companies but it would certainly be easy to do and it would justify the enormous costs of the program.
Other governments have to react as well. The German government is telling companies not to use Windows 8 because of security flaws. If a politician or even a bureaucrat somewhere believes the US government is passing on corporate secrets, why wouldn’t they assist local companies steal from the US? China and the US are already extremely distrustful on corporate secrets and they probably have good reasons.
A culture where everyone believes they are being spied on leads to a vicious cycle where it becomes pointless to invest in new technology.
