If the description is correct then the cyclist was going into the space that they could see in front of them, unlike the Waymo. Someone else said that stop signs are legally equivalent to yield signs for bicycles in California. They probably couldn't see the Waymo because it was occluded by the truck, so how could they yield to it.
This is why straight going traffic always has the right of way if the roads are similarly sized, and it's on the turning vehicle to stop and wait at the turn.
I would also hope that self driving cars are programmed to drive defensively and conservatively over trying to shave off a second or two of drive time.
Presumably, Idaho does have the "Idaho stop", so driverless cars should be designed with that in mind, and operate as conservatively as possible to avoid crashes caused by other drivers or cyclists not perfectly obeying the rules.
Like how California leads the country on emission standards, you'd think the cars following the elevated CA emission standards across the country would also follow the Idaho standard too. Ignoring it is perilous... if a driver incorporates the Idaho Stop into their driving they will not be confused by bicyclists using the Idaho Stop. They might even be more prepared for other things like people running on the side of the road.
Drivers(Idaho included) by and far embrace the California Stop colloquialism if you ask me. The majority of traffic on roads is cars and the majority of traffic rolls through stop signs.
Reading that page, I learned that while California does not de jure have the Idaho Stop, it does de facto have the Idaho Stop. Waymo should account for this.
However I think that is irrelevant, depending on whether the description I heard is correct - it sounds like Waymo turned so quickly after a truck that it could not be certain its path would be clear. That to me seems like the real mistake.
This is why straight going traffic always has the right of way if the roads are similarly sized, and it's on the turning vehicle to stop and wait at the turn.
I would also hope that self driving cars are programmed to drive defensively and conservatively over trying to shave off a second or two of drive time.