Nothing is simple. (Score 1)

"When you can be 100% sure that someone innocent is not hanged, then you have my blessing to kill those convicted of crimes."

By that argument, we should ban Cars. When you are 100% sure that you will not kill someone while you are driving a car, then you can drive again.

Remember 100% sure. Before you argue that you are 100% sure, you are a careful driver etc, check how many road deaths there were last year in your country. I'd be willing to bet a large number of the drivers involved would have said they were 100% sure they would never kill anyone by their driving.

100% is pretty absolute. It's not negotiable.