Former analyst inside large intel agency here. Analysts definitely span the range of technical aptitude. However, most understand what is happening, why what they're doing is specifically legal, and most buy into the narrative that what they're doing is right. I imagine the people responsible for technical surveillance of whistleblowers are a separate, possibly specially selected group. But I'd be willing to be they're selected for being intelligent and true believers in what they do.
I agree with your comments. When I discuss the big picture, I'm talking how their activities and intelligence will be used by politicians on top. The things people in the field are told and what's actually going on often differ enough to impact loyalty.
So, for an example, the analyst might be monitoring aspects of the situation in Syria, including comms of Assad's people, to forward to people who make decisions to compete with that regime. The analyst will know there's others, esp various terrorist groups, trying to topple that regime. The analyst may or may not know CIA and British are giving support to those terrorist groups without regard for blowback that will murder their own. So, their work is indirectly supporting and fueling terrorist organizations that will kill those they claim to protect.
I doubt they knew that. Or their ideology of "protecting" their country was very different than they'd project publicly.
" But I'd be willing to be they're selected for being intelligent and true believers in what they do."
Bingo! That's how the dirtiest stuff remains secret for the longest time. They have to be smart, true believers. They can also be among the most effective given how long they're typically in the game. I like using an easy, fictional example to illustrate this to people. Favorite is the "operator" on Serenity:
