The TVTropes Trope Finder is where you can come to ask questions like "Do we have this one?" and "What's the trope about...?" Trying to rediscover a long lost show or other medium but need a little help? Head to Media Finder and try your luck there. Want to propose a new trope? You should be over at You Know, That Thing Where.
If a story fails to get an aesop across, it could be a Lost Aesop.
If the nature of the story undermines its aesop, it's a Broken Aesop.
If the audience takes away a different aesop from the one intended, it's an Alternate Aesop Interpretation.
Just choose the one that works best for you.
Viewers Are Geniuses could apply if the meaning was well-conveyed — but only understood by viewers already well familiar with the things being discussed.
Is there a trope for when the meaning/Aesop of a story flies over many of the audience's head, either because it requires some thinking to get it, and/or the story itself does a poor job of conveying it? Either way it results in a good chunk of the audience taking away a different meaning from the story than it was actually telling, to the point it erupts many discussions and misconceptions as to what the actual Aesop was.