I will not argue that tipping is a great and perfect system. Though I have noticed many left wingers being against the system for the same reason they hate free markets: meritocracy. They know full well that they will not make it on their merits, so they want a system that automatically rewards them.

"But what about bad tippers?" Well, I am quite willing to bet these same people would disapprove refusing service to those sorts of people when "discrimination" starts taking place.