What if a brand new, human-driven taxi breaks down, blocking the ambulance? Is the taxi company on the hook?
It could be a stalled car, or a fallen tree.
People get overly concerned with blame attribution, and future prevention, when there is often no fault to begin with.
It’s akin to starting a witch hunt after the bad harvest.
SFFD is highlighting to people who live/work/visit SF that so called "AV" taxis are getting in their way. That they were able to move another vehicle to get the ambulance on its way is immaterial. They are saying that in a different set of circumstances where they can't, this car blocks the ambulance. That's the problem, that's the fault.
Your comment sounds like throwing a ladder on the freeway, but you vigilantes better not stop traffic to clear it, no one has hit it. Yet.