Of the roughly dozen questions, I'll try and hit a few points directly to sum up where I believe we ought to be, based on my relatively narrow understanding of US political sciences - please note that many answers to your questions will vary by country and their own democratic maturity.

While I don't agree that there was an implication of the end justifying any type of means, it seems we have already taken a utilitarian point of view. In short, the intelligence community is not allowed to circumvent the constitution and relevant laws (i.e. deprive citizens of their established rights); this is largely in part from the Fourth Amendment (unlawful search or seizure). As legal precedent is an inherently moving goalpost vis-a-vis judicial interpretation, this is a continuous battle in which citizens are aided by transparency and scrutiny of ongoing government programs.

One need not look any farther than the Snowden cases to realize that there is still a strong clinging to this ideal of public transparency, as well as the mountain of evidence that the government ought to be audited to prevent, or at least cease, illegal operations such as PRISM. Judges watch the watchmen - largely in closed-door FISA court hearings, it seems. This bothers me.

However, to think that there is zero benefit to these programs is parallel to naively thinking they are wholly good. I'm willing to wager that there are physical / kinetic and digital events that occur every week which would terrify the average citizen. Transparency is good, don't get me wrong - but there is only so much that some can stomach before feeling ill.

Stay involved in local / state / federal politics. Make noise about things you feel are unjust. Asking good questions is a good thing, but action is what makes the gears turn.