He was a sysadmin and he didn't finish high school, let alone receive an actual technical education -- he's said a lot of very difficult to believe technical things. I don't mean to imply that only educated people know anything important, but unless he just had an amazing aptitude for learning this stuff on his own, I find it plausible that he had only a slight idea of how consumer encryption works and he actually didn't know what he was looking at when he saw whatever made him leak. Who knows without his documents -- I could be all wrong.

At some point I think he claimed that he could've copied the list of all US intelligence assets, even those undercover. Well, given that the NSA developed selinux to compartmentalize filesystem access in such a way as to make such a breach difficult, I am not sure how to reconcile his statements. I also find it beyond belief that a contractor could actually access what he claims he could've.