I mean, let's say, you have a murderer, a very bad person, you have a couple options, you could just put it in a prision, maybe maximum security, nothing bad will ever happen with this, they will be an indifinite ammount of years in there, it's a fair response
or, you could apply a death sentence, and in the way you're saying, so, the most painful one you can get
if you have an option where you can basically punish a murderer, with a slightly more human solution, that doesn't really cost you anything as a person, why would you go the other route?, why would you repeat the same crime that the criminal is being punished for, when you have the option not to?, isn't having an alternative to not murder someone, and to do it anyway as bad as the crime that person commited?
I dont think there is any situation where 1 would be ever justifiable