Criminalizing fossil fuels is insane. The fines should cover the externalities.
No, it makes it so that the outcome is more equally felt across all income levels.
What does someone affluent care if they have to pay a $100 speeding ticket or a $20 parking ticket? That's just the cost of business for them.
Because you want to... hard stop behavior. Parking violations cause harm, so the fine should be a function of damage to society, not some weird fetish to make people feel pain.
If behavior is so unacceptable that you want to prevent it altogether, criminalize it.