I've heard that story. I've yet to see evidence it actually happened though. I don't the experiment with pass a modern ethics panel either.

parables that didn't happen can still be useful

The parable-replication crisis is real though

They can be, but you need to take care as sometimes they are misleading and can even drive wrong decisions.

Aesop wrote a lot of fables that had contradictory lessons.

I have more than once in life realized that one of the two contradictory lessons was correct for this situation, but in a different one the other was correct...

There's a meta-lesson there.