Then there is the complaint that some people "don't pay their fair share." Not including tax evasion (defined as a crime despite taxation itself being theft) , that's because they pay what the law legally permits them to pay.

Although both a billionaire and his secretary are obliged to pay a percentage of their income in taxes, the billionaire has more access to investment opportunities than the secretary. Investments are handled differently from wages, and this alone gives the billionaire opportunities to reduce what is legally required to be paid in taxes. Other discrepancies exist, but you see the point.