Isn't this the same argument that could be used in the context of hospital borne infections?

Autopilot will reduced the number of fatalities in the same way that going to the hospital when you are sick will reduce the number of fatalities. However some people that use Autopilot will die when they otherwise would not have if they hadn't used Autopilot, just like how some people going to the hospital will die from infection when they otherwise would not have if they hadn't gone to the hospital.

I agree! It's a net positive, and I'm in favor it.

But it doesn't mean that people dying from faults "don't matter". Every HAI-caused death is a tragedy, and they certainly matter.

The issue is much less black-and-white than the GP's simplistic view.