Has anyone actually been killed by any Tesla vehicle that was driving automatically (that wasn't in the car itself)? Even on the earlier SAE level 2 "Autopilot" system? I don't remember hearing of any personally.

I don't recall any incidents where a third party was killed due to autopilot, however, I don't believe it's reasonable to extrapolate the general case performance based on prior special case performance, especially when the prior special case performance did in fact result in deaths that would clearly have been avoided by a human driver.

Indeed, but we won't have general case performance until it is acquired. And the statistics show that the prior special case performance did reduce accidents compared to without using the system even if some accidents happened that would not have otherwise happened.