We established the cognitive bias to rationalize it as good.
What would the cognitive bias to rationalize it as bad be?
The reason I believe it is bad is because it violates the spirit of the 4th amendment. It gives incredible power to an organization with no effective oversight. It lacks proper judicial review, and the existing supposed review has been shown to be a farce. It makes everyone using technology less secure. It wastes everyone's resources who have to work against and around the NSA.
Everyone knows they are being watched, listened to, tracked everywhere.
The big deal, though, is the power concentration and chilling effect of such massive surveillance even the Stasi couldn't dream of.
People all want to feel that they're doing good things, and not evil. They'll rationalize all sorts of things to believe that.