$15 is nothing to wealthier people; their only objection will be spending the time processing the payment. But if you are making minimum wage, it's a calculation. Fees are regressive taxes.
If you are poor, you are effectively not welcome south of 60th street; that's for the rich people. If the city wants to raise revenue, how about a tax where the wealthy make an equal sacrifice. If they want to reduce congestion, how about having global businesses like Uber bid on road capacity.
Don't forget the fundamentals that made the US and NY great: All are created equal, the American dream, the land of opportunity, democratic equality, equality under the law. Manhatten is (and NYC more generally is) in many ways more than this being turned into an island for the wealthy.