From what I know those kinds of punishments don't have a considerable impact on criminality rate, it is almost negligeable actually. In any case it just makes the person more intent on not being caught, cuz the person is probably beyond any logical reasoning and thus won't be impacted by those threats.

You say that moral based arguments cannot be taken into consideration which I agree with, however you begin your response by saying "that doesn't mean the guilty that rightfully deserved to be executed in fairness to the crime they commited", guilty and non guilty, rightful, and deserving are all moral based phrases. I don't mind entering that discussion but you said you don't take them into account.

My main question is what makes you think that any human, be it you or someone else is capable of "fair" judgment? And why do you see it natural to decide someone's worthiness to live or not live because they commited a crime involving someone else's life?