Probably the human wasn't paying close attention. That is the problem with level 3-4 automated vehicles: a human who is not in primary control of the vehicle has trouble paying attention and is unable to take over control quickly if it is needed.
That's why I think vehicle automation development follow the path where the computer is not in primary control of the vehicle and can take over quickly when needed. Unlike humans, computers don't have trouble paying attention.
Ultimately, we have to design systems for the humans that actually exist, not some hypothetical superhuman. If it's not safe for actual humans to use then it's not safe full stop. It's not like this is some new issue; it's one of the main reasons why experts have been pessimistic about the prospects of self-driving cars and why existing car companies have been reluctant to deploy heavy automation in the field.
I think he's blaming the folks who put level 3-4 vehicles on the road presumably knowing full well that said human inattention would put people at serious risk of injury and death in the car's edge cases.
