That may be the rules for humans, particuarly people who are always in a rush and won't stay still anyway. With a major intersection turned four-way stop you have lots of humans making very complex decisions and taking a lot of personal risk. If multiple self driving cars make the choice at the wrong time you could jam up an intersection and create a worse traffic issue, or kill a passenger.

It's all a careful risk calculation, those self driving cars need to determine if it's safe to continue through an intersection without the traffic lights their computers spent millions of hours to train on (likewise with humans). That's a tough choice for a highly regulated/insured company running thousands of cars.

If anything, their programming should only take such a risk to move out of the way for a fire truck/ambulance.