Basically, autopilot is mostly used on highways which have a much lower "crash per mile" number then driving in other areas. If you correct for this autopilot is about as safe as a human driver. Read this paper for details. (Tesla cars are still very safe, just not because of autopilot.)
I'm hitting myself for not realizing this, I know about sampling bias! but it diden't help me because I never questioned the numbers.
When reading ANY statistic from now on I'll ask myself: What kind of sampling bias is there? (there's always some)