Believe the electronics are more reliable than mechanical things. This is why in the last thirty years the high tech has grown so huge. If the electronics are not reliable the billions of people in the world will have reported infinite number of instances.
Digital electronics is also very simple. It deals only one and zero. There are no other possibility. Of course during the development stage they will produce countless bugs. The bugs are not due to the zeros and ones. They are due to faulty logic employed.
But you can not use this to argue that the ECM has a bug that caused the SUA. Because I have said the bugs are due to faulty logic. I can not think a reason the engineers will put a faulty logic in the ECM to tell it to accelerate unintentionally.