I was being a tad hyperbolic, which I suppose makes your point. I don't care if we kill them off literally or not, so long as they are confined to life away from the rest of us. I have thought about your point, and I think it has some merit. On the other hand, perhaps we need to ratchet up the reaction a bit as I could also see harm being done by downplaying what is at its core a vicious crime. What is the cost of a victim watching a perpetrator of a horrible crime walking free with a slap on the wrist?
I certainly don't advocate teaching children to fear strangers or filling them with thoughts of horrible boogeymen sex offenders. But once in hand, and convicted, the punishment should prevent further abuses by the offender.