How about the governor of IL that is a billionaire. Should we use the same logic then he isn't corrupt since he doesn't need the money?
I believe needing outside money to get their job makes them beholden to the source of the money, which leads to corruption.
Another thing that leads to corruption of values is signing off on 3000 page "omnibus bills" or whatever they're called.
People agree to sign for what they don't believe in so that other sign for what they do believe in. Not necessarily will people agree that this is corruption, they may say the ends justify the means.