People who would attack the messenger to supress what they have to say...

[Benton D Struckcheon]

98. Well, lets look at the actual story, shall we?

We now know that he went to Booz with the specific purpose of spying on the spies.
The supposition that he had this kind of access is, from everything I know just from working in large companies, more than likely wrong. Far more likely is that he went in with a plan on how exactly to hack into the systems and get as much data out of them as he could.
In large companies, the security model followed is least privilege access. In other words, everyone, including sys admins, gets the lowest level of privilege that they need to do their jobs. There were plenty of things even the sys admins couldn't do at the places where I worked, and to which they, at least nominally, had no access. In practice everyone realized they could hack their way in if they really wanted to, but the check on that was logs that went out every day on things like who logged in with root access, for how long, and for what purpose. The reports had do be signed off every day, and reconciled against approved requests for this access that demonstrated a need for it for whatever the task was. Any access that couldn't be reconciled had to be specifically explained and signed off on by a managing director.
Additionally, every application manager was responsible for identifying critical directories and files that could not be changed except by request. Once again, any change to those files and directories had to be reconciled against approved requests, and once again if no request was at hand the explanation for why it was changed had to be signed off on by a managing director.
One can assume something like this was in place at the NSA.
That being the case, he didn't have this sort of access just by the by. He deliberately hacked in and then proceeded to steal this stuff. The one thing that made me throw up my hands and wonder what kind of operation they're running in there is that he took this stuff using a thumb drive. No one where I worked could use one of those, not even a sys admin. Those USB ports were locked down and could not be used.
If they did allow these ports to be used by the admins, that was just crazy. I tend to think they didn't, and that he hacked the ports to access them for his purpose.
As for your supposition about the missions being illegal/criminal, well, spying is illegal and in most countries gets the death penalty. In the Revolution, the Brits executed Nathan Hale, and we executed Major Andre, Benedict Arnold's British collaborator.
Every country spies on every other country. By definition what the CIA/NSA/DIA do is illegal in every country where it's done. I don't even know why you would bring something like that up.