You'll always be able to imagine cases where a broad toll doesn't perfectly align with a narrow goal, why even waste energy listing them out?

Instead consider how you get the toll to actually do something: in the case of a congestion charge it's by making driving in Manhattan expensive enough to reduce how much it happens for as many people as possible.

Regardless of the corner cases you can imagine, there are more people who drive an M4 that would be unaffected by a $20 charge rate than there are people who drive an 430i. So increase the cost for the people with M4 and you've made your toll strictly more effective... even if there are people who can afford M4s and chose to drive a 430i.