Simple penalties create classes of crime; wealthy folks just ignore the penalty on double parking some poor schmuck because who cares about a $100 fine when you're making $1M?
These regulations are written to discourage unfair acts or behavior that exploites the social contract. It tells folks that the municipality thinks it's right for less-wealthy people to be burdened with providing comforts for more-wealthy people.
Means-tested fines actually get to the point of it: dissuade all people from doing something dangerous, indefensibly rude, et cetera, and not just poor folks.
For some additional discussion: https://www.theatlantic.com/business/archive/2015/03/finland...