I agree with the first part, though not the second. I doubt most judges view the death penalty as a pointless act of spite, and view it more as a logical removable of an irredeemable agent.
My rationale on it is different. I think that if someone commits a heinous action, they either did it for a logical reason or an illogical reason. If it was logical to commit the act, then that is a failure of the system for creating perverse incentives, and change must occur to remove such incentives. If the person committed the act for illogical reasons, then there is something wrong with them, and the should be treated as someone suffering from something. If the individual is deemed truly "beyond saving" then they are suffering a mental handicap and should be sheltered such that they aren't a danger to themselves or others.
By this logic, there is never justification for a death penalty.
I don't think most people will care, so long as their NPC interaction ends up compelling. We've been reading stories about people who don't exist for centuries, and that's stopped no one from sympathizing with them - and now there's a chance you could have an open conversation with them.
Like, I think alot of us assume that we care about the authors who write the character dialogs but I think most people actually choose not to know who is behind their favorite NPCs to preserve some sense that the NPC personality isn't manufactured.
Combine that with everyone becoming steadily more lonely over the years, and I think AI-generated NPC interactions are going to take escapism to another level.