I haven't had time to read the whole article yet but it appears to be a reasonable refutation of the idea that Pope Pius XII eroded the primary end of marriage.
Yes, Pius XII understood the teaching of the Church about what are the primary vs. secondary ends of marriage. But when he started in on NFP, he based his tentative support for NFP on the notion that the "inherent power" of the act was not frustrated (as in birth control or onanism, etc.). What Pius XII failed to consider, however, was that Pius XI in CC enunciated TWO principles which made the marital act licit, one of which was that the "inherent power" of the act was not frustrated, but the other that the primary ends can never be subordinated to the secondary. Pius XII directly quoted the first principle but failed to mention the second. NFP contradicts the second principle because the couple are attempting to partake in the secondary ends while deliberately trying to prevent the primary ends. NFP erodes the principle regarding the primary and secondary ends of marriage. And that's where the floodgates were opened regarding the primary and secondary ends of marriage.
Lest you partake in Pius XII worship, it was also Pius XII who set up Bugnini in his initial liturgical experimentation. Pius XII allowed various "Mass of the Future" types of experiments. Pius XII also opened the door on evolution. Pius XII allowed the first ecuмenical meetings. Pius XII put into place a vast majority of the bishops who would bring us Vatican II. His was the watershed papacy that transitioned into V2.
Yes, I know, this is a great scandal to many SVs, those who cling to an exaggerated notion of papal infallibility.