Parking fines are fair because they are the only way to keep people from parking in spots that need to be free. Without parking fines fire hydrants would be blocked in any big cities. This could learn to a fire that would not be controllable. Fires in big cities have a chance to spread and cost millions in damage. A parking fine could prevent that.
Parking fines are unfair. Land owned by the city is to be used for the good of all citizens. It is unfair for one group of citizens to arbitrarily decide where and for how long a person should be allowed to park. Furthermore, some people are exempted from these rules, and this is unfair. Parking fines should therefore be abolished.