Post-feminism is the standard response to any political movement that actually manages to gain some ground. As the people in power find that somebody is gaining power from them, they will automatically, via basic memetic systems, try to destroy it. This is the system of postism, a 90-degree turn about from the orginal idea.
This is used, basically, to sell books. Once an idea is discredeted, more books can be written about the idea, and about the old idea, and about the new idea and how it took over from the old idea. We can then experience the fun that is post-post-feminism. Oh joy. More rubbish which adds nothing to the actual debate, i.e. equality and liberation.