That sucks, and I love to hate on "self driving" cars. But it wasn't speeding to start with (assuming speed limit in the school zone was 20 or 25), braked as much as possible, and the company took over all the things a human driver would have been expected to do in the same situation. Could have been a lot worse, probably wouldn't have been any better with a human driver (just going to ignore as no-signal Waymo's models that say an attentive human driver would have been worse). It's "fine". In this situation, cars period are the problem, not "self driving" cars.