Not only that, the expectation for safety in automated devices is much higher. The benchmark shouldn't be "as safe as cars driven by Californians"; it should be "as safe as elevators in California, per mile."
The median driver is a risk to his own life as much as the life of other motorists. The average robotaxi is not only an imperfect driver, but also has no concept of its own mortality, which is not the case for almost all the worst human drivers. The benchmark for "safer" is a lot higher than you think.