[Hondor]

The types of mistakes a human and a car are prone to making are different. Neither one has to be a superset of the other. For example, cars are probably better at going round corners at a safe speed while humans can easily misjudge and end up skidding. You could make the opposite argument and say only the most malfunctioning self driving car would choose the wrong speed for a corner yet humans make that error all the time, so humans are even worse than the worst self-driving cars.

Another example. If a self driving car is hit by another car that's running a red light while speeding, we might be more forgiving and say "well nobody could have avoided that accident" but actually we'd be being too soft on the self driving car since it has access to more data and faster reaction times and should probably be expected to avoid that type of crash even when a human can't.