I think this theme is so popular in our society because for hundreds of years that's the meat of how women are seen. Take a long look at some of the fundamentalist cults America houses. Women are tightly controlled. Their lives rigidly regulated. Sex is merely pleasure for a man and something to endure for women. In this world, the breeders are there for just that. To breed women. Think puppy mill....only with humans and the cages are a bit fancier.....until they aren't.