Progressive income taxes are based on the subjective marginal utility analysis that basically says idiots in government can decide if you "need" all the money you make or not and that they are justified in taking the money they decide you don't "need"
And you fail right there.
explain
MArginal utility of money is based on the premise that after you have X dollars that every other dollar is worth less to you so therefore you don't need it
No, it's not. It's not that you don't need the money, but that the additional money doesn't carry the same usefulness. Giving $500 to a minimum wage worker gives him more benefit than giving $500 to someone who makes $100,000/year. He might still NEED the extra $500, but the impact will still be lesser than to the min wage worker.
It is known and demonstrable that the higher your income, the lower the percent of your income is spent on food, shelter, health care. So a poorer person who spends 90% of their salary on food, rent, clothes etc will be hurt more by a 15% tax than a richer person who only spends 75% on necesseties (though his necessities are nicer).