Basically anything negative is rolled up into one signal no matter what the safety aspect is.
Trust me, you'd feel very differently if you were on a bike regularly in the city. The lyft/uber drivers are the most dangerous drivers in the city. Have been since almost the very beginning of this ride "share" app crap.
Any time a driver did something dangerous with me in the car, they got reported and a one star rating with a comment explaining exactly why. If they did something particularly dangerous around a pedestrian or cyclist, I'd tell them the ride was over and to let me off immediately, and then call uber/lyft to report it to an agent instead of just clicking the "unsafe" button in the app.
You don't have a right to drive for a living.
If you do, you damn well should act like it is your living and be safe about it.
The whole fucking reason we have a massive problem with traffic safety in the US is because police and courts and legislators act like it's so necessary that we must endlessly tolerate people endangering others with their cars, and people get "hardship" exceptions where they're allowed to keep driving even after proving themselves to be a complete fucking menace, because "they need to get to their job" instead of "you knew you needed to be able to drive to get to your job and you still drove the wrong way down that street and hit someone? Sucks to be you."
I'm actually a Waymo fan but this particular argument doesn't really hold water.
The only motivation I see that drives self-driving taxi development is reduced labor costs. But that isn't different than what has happened since the industrial revolution.
Probably a better solution is more reasonable speed limits and more consistent enforcement of those limits, but now I'm just engaging in wishful thinking.