Christianity says that the sinful person can be forgiven, and further, becomes a different and better person. That is a fundamental part of the faith. There is also the recognition that even when a person is forgiven and becomes a Christian, there is still a possibility that that person will commit a sin or make a mistake. When that happens, the wayward believer needs to repeat the confession and turn away from the action that is wrong and has offended both the father God and his fellow human beings.
When such a person is in leadership or in a position of power, such as being a priest or pastor, what to do with them becomes an issue for the church. The desire is to restore the person fully to what they were before after they confess and deal with their sin, which includes a commitment to change their behavior. However, there must be a consideration for the seriousness of the actions and for safety of those around the leader.
The Roman Catholic Church has erred on the side of screening errant priests from the secular world's penalties for their actions, and trying to hide these priests by sticking them in less public settings or moving them around a lot. It looks more like cover-up than real concern for the priest's spiritual state or relationship with God. I am sure that if you asked the hierarchy what they were doing, they would say that they were looking to give the priest a new chance to return to his previous state in the spirit of the restorative nature of the Christian faith. To the world, it looks like deliberate ignorance and cover up, and rightly, the church looks bad in the eyes of the world.
I am a Christian. I believe wholeheartedly in the power of God to change people through the work of Jesus Christ on the cross. However, the church--and I mean any Christian church no matter how convinced they are the only genuine church of Jesus Christ--must err on the side of transparency and accountability both for themselves and for the wayward leaders. No where is it portrayed that the church is to be perfect as it lives out the faith in the world. It is charged, however, to be different from the world. That means being different when there is sin in the ranks. The main way that the church can be visibly different than the world is by the way Christian treat both fellow Christians and those who do not believe. It is not an act of Christian love to ignore the obvious wrong doing and its resulting harm to others.
First, the care and well being of the victim must be first. Now, that does not mean that the church tolerates dysfunctional anger, lust for blood or vengeance by the victim. It does mean that the church treats the victim with respect, starts by believing the victim's story, and when needed makes amends to the victim when and if the story proves true. In dealing with the perpetrator, the church works transparently. Obedience to the civil authority of the law, such as obligatory reporting, turning in evidence, and making witnesses and suspects available to me is mandatory. It is not a matter of being mean or punishing the miscreant priest or pastor, it is a matter of holding them strictly accountable for their actions. They must be removed from any position that involves contact with the public, especially the victim population (kids, men, etc) right away. It does not fly in the face of the Christian ideal of restoration to be quick and decisive in action against sinning leaders. In fact, it may help such a person come to their senses by not cushioning them from the consequences of their actions. The hope would be that they would realize quickly the error of their ways and seek forgiveness and turn away from their sinful ways. That is the start of the path for healing for the sinful leader.
Once a priest or pastor or minister has committed to stopping their sinful action--they have made a commitment not to contact children or seduce women or dip their hands in the offering plate--what then should the church do with them? Should they be permitted back in the same ministerial environment in which they fell and did wrong before? If I was in charge, my answer would be "No" in most circumstances. Find another ministry, or vocation not in the church. Even then, the repentant leader's life must be like an open book, totally transparent and open to inspection at any time. The idea must be that we love you, and we accept you, but we care enough about you to demand that you do what you say that you will do, that is, you will stop hurting others.
All of this to be done with gentleness and love, but wisdom. Jesus advised his disciples to be as shrewd and wise as serpents but as gentle and harmless as doves. That advice is just as valid today as it was in Jesus's day.