could be that Tesla making fans believe their level 2 driving automation is better than it actually is and marketing BS terms like Autopilot and FSD contributing to the fatal accident stat. even if the car itself is rated safe by IIHS, isn't that mostly about how well driver and passenger of the car fare when they are involved in different types of accidents? the safety rating wouldn't take into account whether the manufacturer has done its best to accurately communicate capability of its driving automation system to its customers. and i think pedestrian or passengers of other cars dying is counted under the fatal accident stat.
and if you've been in Teslas that are a few years old, you might have experienced phantom braking. random hard braking for no apparent reason. i try to avoid being behind Teslas on the road if i can help it.