The most likely reason "The Monk's Tale" is full of parables is that Chaucer's intent was to make fun of parables and the people who told them.
A parable is a short story, in prose or verse,which purpose is to teach a lesson or principle to the audience. It differs from a fable since fables talk about animals, plants and other nonhuman objects, whereas parables usually have humans as characters. Parables are often associated with Jesus Christ, hence, these are common in religious teachings. This is why Chaucer associates the monk with parables.
