...yeah...nothing..like say..calling the police and CPS? Instead, the Bishop will possibly hear horrible details of sexual abuse visited upon an innocent child...and then watch as the perpetrator gets in his car and drives home..to give his victim a bath and a cuddle!As a Mormon, I have never been in the position of having to seek religious counsel with regard to a sin that involves serious illegality, so I can only speak in fairly abstract terms.
The Mormon view of repentance and salvation requires one to turn away from the sin, and to make every reasonable effort to make amends. It is not at all like how I perceive (possibly incorrectly) the Catholic idea that you can be absolved of a sin merely by confessing it to a priest and doing some minor penance. The Mormon needs for confidentiality between a confessed sinner and a clergyman is probably somewhat different than the Catholic version, but no less valid.
With regard to something as serious as sexual child abuse, this is not a matter over which a Mormon is going to find any easy absolution. The Bishop, in dealing with such a sin, will certainly offer what hep he can in helping the sinner to overcome it, to make whatever amends need to be made, and to prevent it from being repeated. It is very likely that this will require the offender to turn himself in to legal authorities, and face whatever legal consequence will result from his behavior. But that is his place to do, not the Bishop's.
And for a sin this serious, failure to fully repent, (which, again, may require submitting to legal justice) will very likely result in excommunication.
There's really not much more than that that the church can do, or should rationally be expected to do.
It is ethically indefensible.