[lemming]

have autonomous cars really gotten so good that "what if violent criminals try to attack it" is the only criticism left?

No, they haven't. This is (by far) not the only criticism, but it's a valid concern which has literally zero attention to addressing it.

I'm pretty sure not hitting cyclists is still a much larger problem...

Probably, and that one still isn't fixed either.

[gundmc]

What makes you think no one is considering how to address spoofing? It seems likely to me that many of these companies have considered these cases in far more depth than you or I have.