The confessor is completely free to tell the penitent who confesses that he has abused someone that no absolution is possible unless he turns himself into the police, therefore, the abusers won't bother to confess their sins. (If they actually believed in the faith, they wouldn't abuse to begin with.)
The persons whose confidence the law will break, practically speaking, are the victims who mention abuse in confession.
What you are saying is: blame the victim.