We were talking about this article today at home, and my 18-year old daughter said that she thinks that all the NFP crowd are this weird, it's only that articles like this expose the weirdness. Popcak is on EWTN, he's endorsed by the Knights of Columbus, he speaks at the Couple to Couple League and NACHE (National Assoc of Catholic Home Educators). He's not out of the mainstream among neo-Catholic thought.
If that sounds like an extreme statement, his writings aren't any worse than those of another guy who appears in all the same places: Christopher West. Mr. "Naked without Shame" himself takes the Pope's personalism to mean that we shouldn't have to wear clothes any more. He is the putative author of Archbishop Chaput's famous pastoral letter defending Humanae Vitae. The pastoral letter is actually a joke, but it's held up as the very model of orthodoxy. This is actually as good as it gets when you stray into the Alice-in-Wonderland world of NFP promotion.