That's not clear to me at all. It seems clear to me that the person operating the vehicle has ultimate responsibility for how it is driven, whether they're personally driving it or not.
In addition, it may soon be questionable to say that an occupant of a vehicle is "operating" said vehicle if it drives entirely autonomously.
Seems reasonable at first glance, but responsibility makes only sense if you also have the knowledge and power needed for making the right descisions.
Unless the driver is expert in the self-driving car field and core contributor to the car software, he'd end up being liable for events he cannot anticipate and has no control over. In such a situation, the only actually responsible descision would be not to use the car at all.