Earlier quoted context omitted.
Having known other people who have worked for the NSA, they've had to clear any publications with them before publishing (eg, academic papers in a field related to their work, resumes describing work done at the NSA, etc). My understanding is they're enforcable for the rest of your life. I'd expect to see this if anybody published a book without clearance. It's only newsworthy because it's Snowden.
This all makes sense to me. I share your same expectations. Now, I'd also expect Snowden to make sure he is not breaching those NDA's. Afaik, he is not one to make these types of mistakes. Looking forward to his response.
You... you know who Snowden is, right?