But there is no reason why social and behavioral sciences concepts can't be expressed in fiction instead of as scholarly monographs or philosophical essays. And if fiction can be used to explore an individual human soul, it certainly can be used to map a society or a culture. Historical fiction can be used to speculate about what really happened in the past, and science fiction can do the same for the future.

There is plenty of historical precedent where serious fiction has been used to explore societal possibilities; The Republic, Erewhon, Utopia, Brave New World, 1984, even Lord of the Flies qualifies. Some of these are even used as textbooks today precisely because of their social commentary.

The author uses, as you point out, a contrived or exaggerated fictional situation to show what can go wrong, or what mechanisms are at work behind the scenes. You don't need to believe livestock can talk to benefit from "Animal Farm".

Of course, there is always the SF writer who devises an elaborate future society or alien culture in their mind using his or her own political mythology to prove how their paradise would work if only people got smart and accepted it unquestioningly and evildoers quit trying to frustrate it. This is not an exploration of a possibility, but an attempt to establish a probability. The writing is not critical or questiioing, it is laudatory and reassuring. They create a fantasy world that shows how if their ideas were adopted, things would suddenly become wonderful. Heinlein and Rand fall in this category.

At least, with Heinlein you got a little physics with your catechism.