Though for me, I dont need my allegoies to be 100% accurate to real life.
I think the bigger take away is how to live harmoniously with others and willing to find solutions. The real racist is the one who has no interest in helping others live harmoniously.
Its like Hutus and Tutsis in Rwanda. They have their own heritage and their own grudges but the important is to find a way to make both sides happy and function well together.
So to me even if its something intrinsic like elemental powers, where human races are more similar than these types, the point I think is trying to find a way to try to live harmoniously.
Perhaps an allegory Zootopia is even more suited for is people with different mental states like autism or bipolar disorder and the goal is to find a way to have these people integrate.