Moral high ground...?
I believe the conclusion, but don't think the method proves it.
The thing with corruption is that it only happens to good people -- bad people are bad, good people can be corrupted.
Altruism is being slowly trained out of us. We spend less time engaged in social interaction and more time starting at the goggle box (with or without a control pad in hand) and we expect a reward for any good thing we do.
It's conditioning -- pure and simple. We do something good, we expect reward.
So charity bosses organise parties for themselves, send themselves on jollies, up their own salaries -- all from the charity budget -- because of all the good they've done.
A councillor, for all his good work for the community, decides to reward himself by diverting the new bypass away from his back garden.
Some soldiers, having liberated a town, proceed to extract their "reward" in the form of looting and raping.
Christianity got at least one thing right: we're all "sinners", and doing good things is just making us "less bad", not "good". Following that line, we would never get to the stage that we assume the right to select our own reward.