The pedestrian for walking across the street, wearing dark colors, being oblivious to traffic?
The human in the drivers seat for not paying attention?
Uber kind of gets the laundry list: For reducing the number of "safety drivers" from 2 to 1, for not using eye tracking to ensure the safety driver was paying attention, for faulty software or hardware that didn't detect the pedestrian, or for software that after getting the sensor input made a decision to not adjust speed or change lanes, for having some of the worst "intervention" numbers in the industry yet plowing ahead with removing a safety driver from the car...
Who gets the blame?
I'm mostly a "get rid of idiotic safety tags and let natural selection sort it out" sort of person, but on the other hand I feel that piloting a multi-ton killing machine needs to be treated as a huge responsibility.