While I agree with where your essay seems to be coming from, I think you are mistaken, or at the very least, grossly oversimplifying when you say that "the purpose" of sex is reproduction. That is "the" purpose in most species, but it is clearly not "the" purpose with humans. It is one of the purposes. It has been increasingly well understood for more than a century now that sex is at the core of the basic human social structures in ways it is not among other animals, not even among the rare sexualized species such as bonobos. Clues are all around us. It's not a quirk that human females are sexually responsive pretty nearly around the calendar. And human males are not sexually inert except when pheromones from a female trigger interest. Both sexes essentially obsess over sex constantly, albeit in somewhat different ways. And our bodies are constructed to enjoy it in ways too complex to get into in this paragraph. Our physical world is constructed around sexual symbolism, in the designs of clothing, architecture, our vehicles and weapons, places of worship, etc. To say nothing of the arc of our sexuality across our lifetimes being deeply built into our social customs. So, while I agree that it's a very powerful force for people to be trivializing as contemporary culture does, your argument is weakened by the claim that reproduction is the purpose of sex.