It has been claimed that Bradley Manning had access to all this stuff, at the time it was leaked allegedly by him, so others would also had this access too.
What they would not have had is the equivalent of the journalists, media and social networking able to make sense of a lot of boring documents to find the important parts and put them in context.
Do they want to have a situation where every politically aware, literate citizen of the USA (and the rest of the world) knows more about what the US government has been up to than employees of the US government ?
That would appear to be the end result of this policy, and seems a bit silly.