I could be wrong, but I believe part of the reason for having a human behind the wheel is that it allows the testing to take place under existing driving laws. At some point prior to an unmanned vehicle being allowed on the road, lawmakers need to have some kind of framework in place to deal with any incidents that arise. With a human behind the wheel, a fully autonomous car is legally no different to cruise control - it's just a driver assist, and the human behind the wheel is still ultimately responsible for whatever the vehicle does.

In that context, the landscape changes significantly - instead of a self driving car that mowed down a pedestrian, we have a driver who was too busy looking at her phone to pay attention to what her vehicle was doing. From the various articles, it seems that she's not an engineer, and is there in effectively the same capacity as any other Uber driver. If that's the case, she's putting far too much trust into an experimental system. I agree that Uber could do more in the way of technological means to ensure the driver is paying attention, but at some point, an adult with a job needs to be responsible for doing that job.