To believe the the NSA has broken SHA-2 would be to believe that the NSA found something the entire rest of the world combined hasn't found for twenty years.
Why would the NSA or any other intelligence agency reveal that it had cracked/compromised an encryption technology? Wouldn't they keep it a secret as long as possible, to collect as much damaging information as possible, just as the allies did in WWII?
This may be a new strategy AS (After Snowden). If the subjects all believe that everything is known and it is futile to try to communicate, or even to think, the cost of staying in power becomes far less. This is covered in 1984 by Orwell.
It is better to asess their real capacity, and act according to that.