Conversely, even the myth that the NSA reads all traffic also lends credibility to that theory. They don't need to read all traffic, they just need HN commenters to say they do.

Don't normal people already sort of assume that? What's in doubt isn't the potential for the USG to learn these things, but the credibility of their unverified claims that they actually have learned them. I seriously don't see the connection between global surveillance and the USG's ability to lie convincingly: they can already lie convincingly.

Later

BTW: I felt like I responded to what you asked in other comments on the thread, and by the time I saw your comment, many other people had already responded. Nothing personal!