The point is that if one assumes that taxes MUST be paid (debatable, as you say, but stay with me), everyone should have some skin in the game.   It is disingenuous to gouge the top quintile at the expanse of the rest, and then act all bent when that quintile (who controls all power and could in fact just stop paying at all) decides to give themselves a break..  And ironically it is the bottom two quintiles who seem to scream the loudest about why other people should pay more taxes, when in fact they have not earned-- or more accurately - paid for any right to say a word.