That much was obvious. When you build your examples around a sexist experience of sexist media, your examples will themselves end up sexist. I mean, why isn't Zoe buying, too? What is it that Inara's selling? I think we know, and from the heternormative misogyny rises the situation in which a cheeky description of market making has exclusively men buying and exclusively women selling.
I'll be sure to have Zoe and Book make an appearance in part 2. Sorry that my fanfic missed your favorite character.
For the record, I made no connection between Inara's occupation on the show, and her "selling" in this example. I doubt Chris intended such a connection.