Having read your later post on this fable, I understand the context of the fable, yet it seems that most of the responses seem to focus on the donkey only. It seems that the fable illustrates the inevitable consequence of all individuals failing to fulfill their duties and obligations inherent in their station in life. The most important failure of duty lies with the master, as his obvious dissolute behaviors resulted in the discontent of his dog and overreach of his donkey.

Loyalty is two-way obligation: the duty of the subordinate in rendering service towards his master and the obligation of the master in granting privileges towards his subordinate. By this relational debt, societies are bound. When the unworthy master neglected his obligations towards his subordinates in the fable, the entire social system collapsed upon itself, as the dog deserted his station and the donkey reached beyond his station. The moral of the fable is akin to the vulgar sentiment: shit rolls downhill, or as Frank Herbert wrote more eloquently: rot at the core spreads outwards.