I also think that there's a problem with the realistic approach to the story contra the Aesopian interpretation where animals should be seen as human-like being

I also think that there's a problem with the realistic approach to the story contra the Aesopian interpretation where animals should be seen as human-like beings in animal form in order to let the moral be inferred on a figurative, abstract level instead of a literal, concrete level. It's a silly test, because it's ambiguous. Ambiguity is fine in a class setting, but not one where you don't require one canonical answer. It's perfect for something like this, because we assume it's Aesopian and open-ended, but not as a test. I still like it on its own.