I got my renewal notice recently and whilst there is a decrease in the ACC part, it is only about 21%, and is rated by them as Class 1 (meaning the most terrible vehicle to drive

After watching Fair Go, I understand that ACC "evaluate" each vehicle according to some Australian safety survey data. My car is a fairly robust American designed and built 4WD, so one would assume fairly safe for the occupants and vehicle in an unforeseen crash ... and carries a very good five star safety rating under international ANCAP system.
However, reading ACC's additional materials it now appears that they also rate a vehicle in its likelihood to cause damage to other cars or people! See HERE
Isn't this a touch inequitable since a small car can cause death equally well as a large one?