In fact private citizenship combined with government is the origin of corruption. Think about it, as a government official your incentive should be to preserve order, fairness and honor. As a private citizen your goal is to optimize the amount of money you make via business or employment through whatever means possible. That means exploiting loopholes and possibly when no one is looking, breaking the law.
The incentives are orthoganol and it does make sense to have a different set of rights and rules for government officials and private citizens. The minute you take the attitudes of private business/citizens into the world of government you get people creating rules that are corrupt.