If you don’t see how a literal Darwinian struggle resulting in both physical pleasure and a direct demonstration of your god’s philosophy follows a logical chain of thought that’s just a straight up skill issue.

Would it help if you knew that they live in the Underdark, aka the womb of the earth, and their ultimate goal is to burst out of that womb and reconquer the sunlit surface?

Like, it’s not really subtle once you have the required background lore. Pretty blatant metaphor, in fact.