That's an interesting position. I wonder if the opposite is also true: that the more principled and morally righteous the organization, the less it attracts such people and the more it attracts more morally upstanding and intelligent people who like the challenge.

Your hypothetical may be moving on the wrong axis. I think a more appropriate counter example is whether or not positions that no one surrenders any power to attract tyrants. Does a tyrant wish to be a kindergarden teacher?

Not looking for a counterexample, just wondering if the human psychology involved has a dual that can be exploited to ensure high quality, incorruptible investigative agencies.