The Three Virtues Aren't Virtues
At least, not in the sense that they stand for anything morally good. Before I go any further, though, I want to clarify that this isn't me critiquing Bionicle, but suggesting some depth and foreshadowing to the story that I think many people may have missed.
So let's look at the virtues one-by-one:
Unity: This is maybe the closest to an actual virtue, since it implies some love for your community. But what unity really comes down to is "working together," and so how morally good unity is depends entirely on what the community's goals are. The matoran of Metru Nui might have caught on to Makuta impersonating Turuga Duma if they weren't so united behind their leader.
Duty: This one basically means "do your job," which is only really as moral as the job. Most of the matoran of Voya Nui were dutiful enough to follow the Piraka's orders even before they were mind-controlled with Zamor spheres, but that was hardly for the best, and the least dutiful rebels were the heroes in the end.
Destiny: This has a moral dimension if you believe in a destiny written by some benevolent and omniscient higher power but, in the Bionicle universe, Mata-Nui and the Great Beings are capable of making mistakes at best and amoral at worst. Destiny seems more like a way to tell characters to stay in line and accept their appointed tasks. Yet over and over we see characters who do the most good by rejecting their appointed task (Takua, Jaller's team when leaving for Voya Nui, the Voya Nui rebels), not because they think they have some other destiny , but because it's the right thing to do.
Looking at all these points together, it seems clear that the three virtues are really just an order of obedience dressed up in the language of morality and religion. Considering that the creatures of the Matoran universe were built to be nothing more than workers keeping the Mata-Nui robot alive, then it makes sense that they would be taught to worship obedience and hard work. This gives dark undertones to the adoration of the three virtues, but in turn makes it all the more beautiful that these characters developed culture, individuality, and true morality when they had been made as nothing but slaves.
(By the way, this is all on my mind because I'm planning on shirking unity (in my family), duty (to my job), and (biological) destiny by transitioning female in a few months and I wanted to set up a moral backdrop for that).
