I'm willing to bet that the NTSA report on this accident will explore that issue. The one number that Tesla has given included the effect of automatic emergency braking, so it's not a pure autopilot number.
Even if they do show the AP is safer than a human driver, the idea that a machine/software killing people is pretty unsettling to most of us. It's one thing to have a human driver make an error and kill himself and other and another to have a machine do it on a somewhat regular basis, even if in the long run less people die overall. There's something really uncomfortable for society. The justification for it feels very cold and calculated, even if it is right. We've arrived at Peter Singer's trolley car problem.
The trolley problem doesn't have a human in the loop.
Edit: Instead of downvoting me, can the downvoter please point out where the trolley problem involves a human in the loop? This is a level 2 system, where a human driver has to remain alert and ready to take over. That's not the trolley problem.
Oh we let machines kill people all the time. Trains, power transformers, oil rigs...
Sure autodriving is entering the uncanny valley and that's different. Lots of things are different about it. Instead of prosecuting one person for causing an accident, now a whole line of vehicles is 'at fault' and maybe get sidelined. Good news there is, they can all be fixed at once.
It'll end up more about the law and insurance implications, than what we feel about it.