I know what you mean. I wish the other 80% would get a little more pro-active about defending the integrity of the FBI. That will take more than just keeping themselves clean.
I believe that the honest fraction of the FBI and DOJ are unwilling/unable to do anything about the corruption due to a combination of two factors. 1) The honest a members are kept as far from the levers of power in the agencies as possible by those who are corrupt (i.e. kept out of DC and NYC) 2) The corruption is most entrenched in those parts of the agencies that are supposed to keep the rest of the agency honest. Thus trying to do something about the corruption is the end of their careers even if they try to do it quietly. The MSM will happily destroy them when they are willing to try to expose the corruption publicly.