You say it's barbaric to kill someone in a possibly painful way. Maybe these 'possibly painful' methods have been mentioned in the thread itself, but it wasn't part of the actual title/topic? Are you saying that if a painless way WAS used, you'd not be so against it (as it can no longer be considered barbaric)?
l
It would still be barbaric just not as much.
And as said it costs no more in resources to lock someone up or kill them.
And no i do not consider locking someone up for life as barbaric. We don't suddenly remove all their basic rights and torture them every day.