This is a tough question and you don't really go in depth with your own stance.
There are different degrees to the "eye for an eye" attitude. As you mention in general you treat people like they treat you. Ok, makes sense. I am on board.
However the eye for an eye attitude would also mean that if someone kidnaps, tortures and kills your child you'd also have to do the same to their child. Now would you?
I most certainly wouldn't. Yes the guilty should be hanged to death. However I don't see myself capable of doing the same thing in return not even to the criminal himself.