The “humans” in question can also be read as the the old aristocracy. In Orwell’s time and youth they were much more influential in Europe than they were by his death, especially in Russia. However, I don’t think the ‘humans’ were ever important in the book nor that they had a specific target. They were just background, really, from start to finish.
I didn’t care much about the themes. I was looking at the logical, rational, literal meaning of the text. And it still makes no sense. This isn’t really a fantasy story, nor until the very end anything approaching a thematically driven movie. It was made as a solid mystery story with strong philosophical overtones; I don’t believe shooting the logic of the mystery in the back was a good idea, no mater what it does for the philosophy.
But tis almost never read outside of college courses - and even there essentially defies any coherent meaning until explained.
You say it’s still around and therefore must have meaning. BUt note that the text is almost always played as a total fantasy: only a handfulk of people at all comprehend it has or had a deeper meaning. Aditionally, I think you overrate the universal aspects of the book. I don’t think it has terribly much to say outside of the political commentary, although I can see how one would get that out of book 4.