Well, in the former case, that is the fault of the driver (or another driver). In the latter case, it would be the fault of the manufacturer. It's not even remotely the same thing. Remember those out-of-control Priuses, where the manufacturers were at fault. Toyota got plenty of backlash for it.
I find this an interesting question. With the exception of OTC and prescription drugs (for which there are still lawsuits) I have trouble coming up with other consumer products when used as directed and properly maintained are still directly involved in killing people because... well, stuff happens. This isn't an argument against using autopilots but it is an issue that hasn't been really addressed so far.
