Sorry David, but you are engaging in an intellectual sleight-of-hand when you lump porn addiction in with sex addiction. Whether you find the existing evidence of sex addiction persuasive or not, there is ample evidence that novelty-at-a-click causes addiction in some brains - whether it arises in the context of excessive slot machines, videogaming, Facebook or Internet porn use. Perhaps you haven't been keeping up with the latest Internet addiction studies (which include, but are not limited to, porn use). The studies show brain changes that are fundamentally the same as are seen in drug addicts' brains.
Your position that sex addiction is a myth also shows a lack of understanding of the true underpinnings of addiction, which are tied to dopamine dysregulation and related brain changes. It is the presence of these changes that make an addict an addict...not the particular activity engaged in. This is why the American Society of Addiction Medicine publicly stated that both food and sexual behaviors *can* cause addiction in some brains. It's too bad the author of this piece seems unaware of this statement by the leading experts in addiction. Here's a link to their FAQs related to the statement, which discuss the existence of sexual behavior addictions. http://www.asam.org/docs/default-document-library/20110816_defofaddiction-faqs.pdf#search=%22long%20version%22
Incidentally, equating disbelief in sexual behavior addictions with "sex positivity" is particularly unsettling, as those who become addicted to Internet pornography often report sexual dysfunctions (delayed ejaculation, inability to sustain erections with real partners and so forth), which only reverse themselves when they stop using Internet porn for a few months. There's little more "sex negative" than erectile dysfunction.