I have a hard time believing that a human driver would be as slow as this Waymo, or even slower. I drive my kid to school where it's posted 20mph and there are cameras (with plenty of warnings about the presence of said cameras) and witness a constant string of flashes from the camera nailing people for speeding through there.

Hardcoded limits are problematic because they completely lack context.

On that very same road with a 20mph limit, 40mph might be completely safe or 3mph might be extremely negligently dangerous. It all depends on what is going on in the area.

Considering the car hit the child at only 6 mph and the kid just got up and brushed themselves off, it was plenty slow enough.

Nobody was injured.

A small child jumped out in front of it, which is about the worst case scenario you can have... and the kid was fine. So it sounds like it was slow enough?

Maybe. That level of safetyism seems pretty unreasonable when humans are 100x worse and still allowed on the road.