There are various honorable reasons to be against the death penalty. It's arbitrary; most first degree murderers won't face it. It's applied unequally for class and race. It's more expensive than life imprisonment.
All reasons to fix the system, not necessarily do away with capital punishment.
It doesn't act as a deterrent.
I've noticed most people who bring up this are those opposed to the death penalty using it as a straw man argument. It's more about justice than deterrence.
And yes there are some people who really do take the "Sermon on the Mount" seriously/literally and are fiercely opposed to the death penalty for religious and/or moral reasons. The Catholic Church in particular has some powerful writings and arguments against it. I'm not bothered by the concept of fair retribution but I'm leery of giving this society (particularly the State of Texas) the ability to kill people.
And I can fully accept and respect the Catholic position because it's
consistent, i.e. they don't oppose the death penalty while supporting abortion.
