“That would protect the employee in case of later legal action.”
No, it would not. If they needed to know, someone above them would say so - like the President. When told they do not have access, they can complain to the President.
For an imaginary example, the SecDef doesn’t need to know the details of how a specific guidance system works. He needs to know IF they work, but not the technical details of how and why.
He might need to know we have people inside of X spying on others, but would not need to know their names or how to contact them.
“Oh, but we need to trust them!”
Hillary Clinton was Secretary of State. Leon Panetta was SecDef and also head of the CIA. Political appointment.
That is why President Trump is going to have to step up on this issue.
We cannot have bureaucrats dictating national security policy.
That is an unacceptable disaster.