Priests and clerics—good men of ‘God’—were required to attend seminaries where they were taught how to inflict the most pain possible on another human being. This is how important it was to them that people publicly confessed and recanted their beliefs in order to reinforce the social rules.
Torture to gain the confession was often a behind-the-scenes thing but the punishments were not only public but dramatic and thematically related to the particular societal rule they had violated. It was a kind of prophylactic policing.
An adulterous woman had to interact in her community wearing a scarlet letter ‘A’ so everyone would know what she had done. A gossip might have dead fish hung around his neck for three days to demonstrate the stink of their words. Someone with a ‘hot tongue’ might be dunked in ice water. But someone with greater crimes against society and/or God might be determined to be in possession of the devil and have every bone in their body broken so that the devil had nothing to hold onto. Not surprisingly, some punishments were not survivable but the church deemed that the person’s eternal soul was saved at the last moment and so their job was done.
There is evidence that many of the men of God who were tasked with these punishments truly believed them to be both effective and just. They weren’t sadists (just fanatics).
Taken from The Great Courses’ Explaining Social Deviance Lecture 2: Demonism