I already covered this in my post. If we could determine guilt with 100% accuracy kill them. We can’t so settle for locking them up forever. If they’re found to be innocent later they can be released and compensated for their time. For raping adults and killing kids the same criteria as raping kids should be applied.
Or “killing adults is a bad thing”? Or “drinking and driving is a bad thing”? Or “robbery is a bad thing”?
These are all very different from rape or harming children and there can be other factors to consider regarding motive that would have to be taken into account when doing the sentencing. For instance in the Gary Plauché case. He murdered the man who kidnapped and molested his son. If that’s his threshold for murder, it’s unlikely he would re-offend (and he didn’t for the rest of his life).