The purpose of confession is not civil jurisprudence. 

You're silo-ing things. Think more thoroughly and comprehensively. 

Today, the government argues for snitching on child rapists

Tomorrow, wife/husband beaters

The next day fathers who don't pay child support

The next day adulterers (in support of divorce proceedings)

The next day tax cheats.

The next day...no one goes to confession, except women and some men who want some pitiable priest to hold their hand and pass out tissues, not interested in absolution, amendment, re-union with God and His Church.