It seems pretty clear to me (if you've been to SF recently) that autonomous cars react to pedestrians quicker and are much more careful around pedestrians than human drivers.

You can certainly take the attitude "I will only agree with having autonomous cars on the street once they are provably 100000000x safer than a human" but I don't think that matches most people's view on what constitutes safety.

Also, that goes pretty strongly against the American ethos, where we let people make their own decisions in terms of what kind of things they buy, within reason.

We already know that SUVs are more dangerous for pedestrians, but I think most of us agree that making SUVs illegal for this reason would not be a good idea, and is against the American ethos.