I’m not sure I think there is that much of a difference. Everything fictional is made by a person living in the real world, so there is always going to be a connection. You can’t just view it in a vacuum

How many fantasy books (and sci-fi but I read less of those) have not touched upon subjects like corrupt religious institutions, how to be a good leader, the nature of humanity, loss, love, the consequences of war and more. Sure if you look at everything on the surface it might seem like fancy swords and pretend people. But any well written book will usually have lessons or views relating to the real world. A bad one might not, but neither will all non-fiction books (Take celebrity biographies made only to make money for example)

Like any book you just have to engage with it and think. I don’t understand why something would have to be an exact replica of our world for it to matter. The important part is you and your reading of the text, what you take away from it.

Allegory being less direct is also the entire point of allegory (avoiding censorship, being allowed to express thoughts you wouldn’t otherwise etc.). Fiction allows a distance to our own world that I think is very beneficial at times. A way to force people to engage with ideas they otherwise would have scoffed at. It’s more digestible and easily approached than stating things outright

Non-fiction is important, yes. Many people could stand to read more and it’s important to have knowledge about our real world in order to live in it. But it doesn’t mean fiction doesn’t have a purpose

Edit: sry it got long

Also obviously you shouldn’t apply things one to one, but engaging with ideas in abstract ways is not unnecessary or not beneficial. And you can do it with anything, I’ve seen amazing societal analysis’s based on the sims with in depth discussion on what parts of our irl society that the game reflects (and not)