It's a difficult dilemma. Priests I have talked to admit that occasionally they feel as you do. But they are bound by their oats of obedience to the teachings of the magisterium of the universal church. In the context of the sacrament of confession, the priest is the intercessor and acts in persona Christi, and is vested with the power to grant the penitent absolution, which typically involves some act of contrition. None of this makes the priest God, or usurps the power of forgiveness through the sacrifice of Christ, but it provides a means for the dispensation of the grace of forgiveness and repentance. Because of the connection between the penitent and the divine nature of the blessed sacrament, the church asks for confidentiality.
In the interest of full disclosure, I am just a clunky convert, so I be wrong about some of what is discussed above.
Violating the Great Seal of confession is a sin against the Holy Spirit. Which is much worse than any sin against the 6th commandment, no matter how heinous.
The penance given for such heinous crimes against the innocence of children would normally include restitution. The penitent would not be absolved of his guilt unless he made restitution, which would include turning himself in to the authorities for punishment.
This is nothing new. Secular governments throughout history have attempted to compel confessors to break the seal and martyrdom is the final outcome.