Hipsters are so tainted with irony, so buzzed with chi-tea lattes that they refuse to wear the political schwag of their left wing buds. They are forced by their ideology of hipsterism to wear Trump hats to show how deeply contrarian they are and to display their contempt for the system. Nothing is more ironic than ironically wearing a trump hat when you are a registered socialist. They do it for the lulz. And because they are against lefties taxing their trust fund.