The second someone works for the FBI, with that being their main motive and only plan, they may be a lot of things, but hardly a hacker. I guess everybody has their own definition, but to me this is like saying "water needs dry surfaces".
Everyone sells out sometime. Is someone that believes in justice even in spite of an inelegant set of legal boundaries a particularly exceptional case?
"Never trust a traitor, not even one you create" -- Baron Von Harkonnen
This strategy has been working very well at DARPA.
The FBI and other organizations like it emphasize strong (blind) loyalty in their hiring criteria. That is the opposite of what makes someone a hacker. Even if a hacker did end up working for the FBI, he or she would be an asset, not an employee -- they would be handled no differently from gang snitches.
Considering that penetration testers are usually certain they'll find a new 0-day when they work on a new system, why bother with back doors?
Why wouldn't they just have both?
For your own safety ;)
I think this is part of a sadness buffer underflow attack by the FBI.