[spklnraz]

Then what would you do with them?

With who? Children who commit crimes?
To a juvenile correction facility,
where they are socialised into society like proper adults.

Insane people usually go to asylums.
Sane people don't go to asylums.
So when an insane person is corrected to fit the standard of society, he gets out. That's why it can be a life sentence, some people just never learn.

Sending a murderer to prison for 15yrs,
means that you'll have a murderer coming out of prison in 15yrs.
It doesn't help anyone.

Child molestors probably have some deep issues to deal with, being molested themselves, seeing it as normal, loving, behaviour. They need help. As do the children ofcourse, so that they don't become traumatised and go out to become sinister adults themselves.