Fear of the unblinking eye
I've been thinking that the NSA "surveillance state" story disturbs many people because it runs counter to our presumptions of innocence and privacy. We understand that citizens should not be punished as criminals without due process. We also think well-meaning citizens will not be treated as criminals. Law-abiding people strolling down Main Street expect to be treated differently that prisoners shuffling through a cell block on their way to the exercise yard.
But of course, we don't really expect agents of the government to be completely blind. They couldn't detect and thwart or punish lawbreakers if they were. And if the government could not keep any secrets, it also would not be able to respect the confidentiality of its dealings with any citizens, or pursue proper legal cases against real miscreants. Does anyone want those information-yearns-to-be-free Wikileaks types to expose and publish the IRS database of all taxpayers, or confidential law enforcement data that would thwart the hunt for a dangerous killer?
This is all really a matter of degree. Most people don't mind the agents of government observing us in a relatively casual manner, or keeping certain things secret. We're comfortable with more intensive surveillance when due process is observed, and specific persons of interest are identified. It's not really a choice between Big Brother and no surveillance at all, any more than government is a choice between bloated all-controlling socialism and lawless anarchy.
One example of this principle that comes to mind is traffic cameras mounted on street lights. Some areas have encountered heavy resistance to automated systems that snap photos of license plates and issue citations. The people raising those objectives don't think everyone should be allowed to run red lights or blow past the speed limit with impunity. They obviously don't relish the thought of getting pulled over by a human cop, but they have no objection in principle to such officers performing their duties. (How often have you, or a fellow passenger in a car, wondered "Where the heck are all the cops?" when you see someone driving stupidly?) But they get nervous when the laws are enforced by unblinking, merciless robots.
Similar reservations can be found in the matter of domestic drones - not the armed Predator variety, but the use of domestic drones in domestic airspace for law enforcement, which is going to grow very rapidly over the next few years. A police drone isn't doing anything that an officer in a helicopter couldn't do; they're just impersonal and relentless. People who think nothing about seeing a "bear in the air" cruising over the highway are going to get jittery when it's a menacing UAV painted in sheriff's colors.
Unfortunately, those presumptions of innocence are wholly incompatible with the maternal, activist super-State, which is very much in the business of punishing activities that are not criminal, and is ravenous for information about her child-citizens.