We're going to do a quick pass through the everyday conditions when Chaucer lived. He is so often seen as merely a "jolly storyteller." But an idea of the milieu in which he lived, the experiences put upon him, will allow for deeper, broader possibilities.
His travels took him all across Europe. He knew a great deal about the Black Plague, for starters. It often ravaged Europe, and it struck England five times during his lifetime. Most deaths were in rural areas among peasants and farmers. Whole villages might be wiped out.
Royalty and other landowners expected to receive fruits, vegetables, meats, cheese and other supplies as usual from those who worked their lands, in spite of the depletion in number of able-bodied workers. These expectations led to the "Peasant Revolt." When a multitude of peasants marched on London in 1381, King Richard II agreed to some of their demands. But, even as the leader of the march spoke to the king, the Mayor of London struck the peasant dead. That ended the revolt and the king's agreements. (Peasant uprisings were not tolerated. In France such protestors were massacred.)
The actions of the Inquisition, though not yet come to England, were familiar to Chaucer from the Continent. Its proceedings were an attempt by the Church to eliminate medieval heresy. Torture and burning at the stake were used to encourage conversion.
It is thought that Chaucer may have participated in the Lollard movement in England, which sought church reform. Although "reformers" were greeted with hostility, people of many ranks--merchants, townsfolk, clerics, lords--were attracted to the Lollard effort. Four noble friends of Chaucer's were among them. By 1399, however, after royal and ecclesiastical pressure, the movement had been silenced.
In 1378, the Great Schism rocked the Church. Two rival popes existed--one in Avignon, the other in Rome--each denouncing the other. That rift was never resolved while Chaucer lived. This and other signs were interpreted by a faction in England to show that the time of the Anti-Christ and the end of the world were at hand.
If all that were not enough to endure, political tensions in England were inevitable. The reigning king would be at odds with the lords; the lords at odds with each other; and, with a king's successor, all circumstances had to be reevaluated. Chaucer's peace and prosperity depended on his ability to maintain a favorable relationship with the royal court. If one fell out of favor, as happened to the poet's friend, Thomas Usk in 1385, one could be hanged and beheaded.
In 1388 "The Merciless Parliament" tested all the poet's skill at "diplomacy." This parliament condemned the advisers of the adolescent Richard II. Without formal trials, those accused were drawn and hanged. All had been friends of Chaucer. The parliament also dealt harshly with Richard's lesser supporters. Many were executed or exiled and their property seized. Heads, and other body parts of those executed, impaled on spikes at the city gate, were intended as a silent deterrent.
Those who dealt so dreadfully with the people were figures of authority. It was believed at that time that those in positions of power had been chosen by God. Therefore, to oppose them equaled high treason. How could one handle being immersed in such unrelieved stress? It's just human nature to find some way to vent frustrations.
All the factors we've looked at would make the fourteenth century fertile soil for hidden protests such as allegory, where, if cleverly done, those in authority wouldn't see the second meaning. I found a wealth of necessary information on the subject in Angus Fletcher's Allegory: the Theory of a Symbolic Mode. I have no doubt Chaucer, a writer admired by his contemporaries, a man steeped in the conditions of his times, would be capable of expressing heartfelt protests with well-chosen words.