A comment below raises the excellent question as to how the abusers can live with themselves. How can they lead outward lives of piety and inwardly be sacrilegious criminals.
Their spiritual ancestors the Pharisees had a similar ability to impress men by outward shows of piety but inwardly were full of rapine and evil: they were whitewashed tombs full of dead men’s bones.
Jesus had little doctrinal disagreement with the Pharisees: unlike the Sadducees, the Pharisees believed in the existence of angels and the resurrection of the dead. But they observed the minutiae of the Law, while forgetting justice and mercy and love.
In addition to Phariseeism and hypocrisy, the abusers suffer from some deep desire to control and use others. That is why they keep records of their crimes, records which expose them to prosecution and conviction.
They control others by putting on a very convincing façade of good works, as well as by abusing victims. At the heart of the abuser is a desire for control, for power. As the Catholic priesthood has often been presented as an instrument of power (whether spiritual, political, or psychological) it attracts such people.