The purpose of pornography is to arouse desire in the absence of desire, to raise appetite where no hunger exists, so as to provide a market in which the purveyors of pleasure can make their living and their profits. People who have no desire to eat a piece of bread and butter, because they are not hungry, can be stimulated to desire chocolate if the chocolate is presented to them as something more than food, as ecstasy, rhapsody or orgasm. Commercially produced food is also fake food, not made principally of the substances mentioned on the label, but with chemical analogues and fillers, and laced with taste additives and excessive amounts of salt and sweeteners. Your healthy yoghurt-coated apricot pieces are mostly vegetable fat and sugar, neither of which is mentioned on the label. In a similar way, commercial fast sex is fake sex, divorced from both passion and reproduction.
Food advertising sells fantasy food and sex advertising sells fantasy sex.
Just as the advertising of fast food and confectionery has eliminated appetite so that no one now knows what it is to work up an appetite, or that hunger is the best sauce to any food, pornography has eliminated desire. Food marketing has brought eating disorders upon us, and it is as likely that sex marketing will have the same consequences. There was a time within living memory when for most people, fast food and fast sex were both unattainable. The nation had much less food and much less sex than it has now, but it is very possible that it enjoyed both food and sex more than it does now. An orgasm prolonged for more than a few minutes would soon begin to pall.