Hidden Reasons

To tell the truth, even though the overall environment in Europe from the Middle Ages to the Renaissance was barbaric and dark, the Church would not lightly judge someone as a heretic.

Historical records indicate that the vast majority of witch trials in Europe were concocted by local people, and the proportion that reached the level of the Church was very small.

Indeed, although there were likely individuals during the Medieval to Renaissance period in Europe who could be called utterly corrupt, the types who would go directly to hell and reside in the eighteenth layer of its basement if there were a doomsday judgment, they didn't often engage in human barbecuing.

To give a simple example, when the British prosecuted Saint Joan, their greatest fear was that Joan would appeal to the Church.