I was really torn on this issue until reading your post. After all, if someone is truly repentent, then they should be willing to turn themselves in and endure the consequences. Easy confession, i.e. just say you did it, then go on living as you did before, isn't true repentence.
I’m pretty sure that priests are not canonically required to instruct penitents to turn themselves in. In fact I think it’s almost the opposite. The priest is not allowed to “force” a penitent to do anything that would damage the penitent’s reputation.
For instance if the sin was theft the priest could require the penitent to give what was stolen to the priest who would then return it, unless even that would give away the person’s identity and then the ill gotten goods would be given to charity or some other solution arranged so long as the thief didn’t profit from his crime.
Beyond all that we’re talking about child abuse here and as far as I understand, most of these “people” (and I use the term loosely) don’t think they’re doing anything wrong anyhow.