First things first: There is NO BDSM in this book. There is plenty of D/S, slavery and abuse, which is NOT the same.
I think I got the idea of how this "society" is supposed to work.
Not really a spoiler, just my own thoughts:
Mothers are at the top of the food chain with multiple communities with different purposes directly under them.
I think it would be safe to assume that there is an agricultural community or a pharmaceutical community, among many, unaware of each other.
They send their products to mothers, who distribute the goods among the rest, based on individual needs. In the same fashion they distribute little kids among the communities according to kids' special character traits.
What does this particular military community contribute to the pile? Why are the men in it reduced to reading little kids' books as if they were holy scriptures? Why do boys have to go through the woods and then be "civilized"? How did humans in general end up in this predicament? I can only fantasize and spend days obsessing over it.
I am not sure if this book is "thought provoking" or just a bad move on author's part. My impression is that she didn't want to think it through and supplied us with the necessary minimum, while concentrating on her usual "breaking a boy" plot. Look at her other works, they all come down to just that - taming a wild boy, breaking a new boy, teaching a boy submission and rules, adapting a boy to an alien (literally) environment and so on, more of the same in different settings and variations. Fun, I can't deny, but her books (at least the ones I've read) all come down to the same thing.
I am moving onto book two, because I am still curious about how this world came to be and because I already own it.