Playing devil's advocate here, and watched a bunch of spy movies... What if Snowden is still a CIA agent (he was a CIA agent for years before NSA) and this is actually a snowjob/whitewash by the government to deflect attention or essentially control the message about news they knew would be released (diffusing that/controlling that message) and black-ops about China, Russia, Cuba + Venezuela how they treat/process po…
Ill go a step further. Snowmen is really a bellwether event created by this administration to either provide a redemption story for the Obama administration, should the public object too strongly-- or to test if surveillance can be taken much farther (if the public remains apathetic)
It's not useful scrounging up, uh, conspiracy theories for how it happened unless there is evidence.
The only argument you're invoking is abduction - that no other approach fits the facts. But the thing about the NSA is the level of spying and power that's demonstrated gives a strong indication they just don't have much reason to care what the public thinks. The average NSA bureaucrat isn't worried about the public at all but what argument their boss or colleague will use against them. And letting out information goes so hard against the default impulse that letting information out intentionally seems way unlikely, even as part of a clever master plan. I mean, if we're wandering to wild speculation land, the NSA has dozens of potential master plans. One that releases information and makes them look bad wouldn't do well in the "master-plan competition" - held yearly at Area 51!