how do the priest and barber decide which books to burn and which books to save? What does this tell us about the books and about reading in general?

In the novel, Don Quixote, the priest and the barber begin an inquisition and visit Don Quixote's home, where his neice encourages them to burn all of the books. But the priest doesn't want to do that. They are only looking for books of chivalry. When he says that all of the books of poetry might be ignored, the neice argues that then Don Quixote might become a poet....something that would be worse than what he is currently obessessed with.