A more pointed example might be: indiscriminate surveillance can be used by corrupt officials for political persecution of their domestic political enemies. Look no further than the recent IRS scandal to see the willingness and ability of people in positions of power using the levers of power against political opponents, even when the stakes are low or petty. The NSA database of information represents an unbelievable trove of opportunity for the very real prospect of the arbitrary abuse of political power, both by people within the U.S. government and by anyone who manages to illicitly gain access to that information (e.g. foreign hackers—and there's some evidence that Chinese hacking attempts on Google were aimed at the interface Google set up to provide information to the government).

There's a difference believing that this type of surveillance is good and believing that Snowden should be prosecuted for leaking in the way that he did.