Maybe, but it is a deception, because the setup is given by the storyteller. So if you think for yourself, you do so with the assumptions given by the story.
I still think it is simply a device to sway people's opinions. Otherwise, why not just give some condensed facts about the real world?
No, I don't agree with that proposition at all. Rhetoric is something you don't have to like, but to dismiss it entirely as you have done in this subthread is to do a disservice to yourself. I happen to find rhetoric fascinating, as it has to do with human communication and interaction.
If you've ever given a presentation, you've performed rhetoric (the art of using language to persuade). If you've presented based on measurable facts, you've still used rhetoric. (Indeed, without using other language to help organize and interpret the facts at hand, it's very easy for facts to be used to confuse an issue.)
Parables are rhetorical devices usually used to illustrate a moral or religious lesson. Yet, they can also be used to illustrate other lessons, too. A quick search for "secular parables" resulted in the "Parable of the broken window" as a lesson to be learned about economics.
I still think it is simply a device to sway people's opinions. Otherwise, why not just give some condensed facts about the real world?