OP's point implies that it's a predictable byproduct of the system design because people consistently work to minimize their tax burden and the effort scales with their means. Wielding money to influence lawmakers seems bad, but is also a certainty in a system where your lawmakers are willing and able to legally accept it.
If you want to hold people morally responsible, why hold entities designed to maximize profits to a higher standard than lawmakers who are there to represent the interests of the people?
And if you want things to change, why fixate on moral judgements about legal behavior instead of systemic changes that yield better outcomes within the constraints of humanity's natural tendencies?