Not could. Had been and were, for which there was growing evidence culminating with the Snowden files. I don't disagree that they had a considerably larger impact than what went before. You're absolutely right in the sense that once the stories of GCHQ's black boxes, the EUP's documented disclosure of Echelon [0], room 101 and so on and so forth got outside the circle of people who were familiar with them they became FOAF stories and conspiracy theories and weren't part of any mainstream discourse, but there was a bit more to [it] than abstract hypotheticals and general 'power corrupts' cynicism.
[0] An Appraisal of Technologies of Political Control. http://www.europarl.europa.eu/pdf/jadis/2013_12/8.PE4_AP_PV!...
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