The thing is, usually the mistakes made by a computer appear obvious, as in "even an idiot wouldn't make that mistake". For example, a human would have to have really big problems with hearing or language to hear "make a payment" as "cancel my account". If the sound quality is bad the human would ask me to repeat what I said, I would say it slower or say the same thing in other words.
Same thing with cars, people can understand the limits of other people (well, I guess I probably wouldn't be able to avoid the dog too, it probably ran out too fast), and when a software bug causes a self-driving car to crash, it will be something like "the dog was crossing the road from the other side, the car started turning towards the dog and hit another car while attempting to deliberately run over a dog).
Also, to err is human (or so the saying goes), but a machine should operate without mistakes or it is broken (the engine of my car runs badly when it is cold - but that's not because the car doesn't "want" to go or doesn't "like" cold, it's just that some part in it is defective (most likely the carburetor needs cleaning and new seals)).