this can be true, but a lot of the time, because the author has the ability to write anything and not be constrained by reality, what they write often isn't a critique of a real situation so much as it is a reflection of their own internal biases and internalized propaganda about that real situation.

the example that most immediately jumps to mind is Rowling's house elves being slaves and also liking being slaves and actually you're a bad person if you don't want them to be slaves anymore. I mean, sure, it could just be an entirely made-up fantasy race that likes being enslaved, but it could also be internalized propaganda about other races, especially considering that she was born in the decaying/fallen British Empire.

So I would argue that the books in the thread image are, obviously unintentionally, actually more about how propaganda about "authoritarian" states during the Cold War influenced the authors of that time, rather than those books saying anything about the Soviet Union.

I think it's generally best to not rely on fiction when trying to make a point to others who don't already agree. It can be a nice bonding moment between two people that already agree - we could talk about how Don't Look Up if we both agreed about humanity's role in climate change and how many people don't give a shit because they think they're invincible or already got theirs, but bringing up the film to a climate change denier just isn't going to go well unless approached very carefully.