Pius XII opened the door to this Catholic birth control with his ill-considered speculation in his speech to the midwives. As the article to which you linked stated, it would be ONE thing if under some very specific circuмstances, a confessor might allow/tolerate this practice for a specific penitent, and quite another to publicly declare it as licit. From there it was just a matter of time before it became widespread.
Pius XII caused great scandal by stating that this practice could be justified by "eugenic" considerations. In so doing, he adopted the very language of the most ardent proponents of Abortion and Birth Control. Margaret Sanger, the ultimate originator of Planned Parenthood, was one of the pioneer "eugenicists". Eugenio should have thought better than to use the term eugenics.
I agree that the reference to eugenics is a bit unsettling (particularly as the parent of a profoundly autistic child):
Is Pius XII suggesting that the world (and parents/families) and Heaven are better off without such persons? That the greater care they require outweighs their right to life? That if you risk bearing such children, it is better to abstain?
I will tell you this: For all my rough edges and imperfections, my son has made me a much more compassionate and considerate person than I was before he was born (believe it or not), and his very presence and dependence is a constant opportunity to exercise charity. He is a great gift from God as a means to sanctification for the rest of us.
But Pius XII seems to represent a pre-conciliar shift in moral theology (which would become dominant at and after the Council), which shifted from “sanctity of life” to “quality of life.”You see this shift particularly present regarding medical end of life issues, NFP, and abortion rhetoric.
Now the SSPX seems also to have become infected with a preoccupation with “quality of life” considerations (not yet in end of life or abortion issues, but definitely in NFP).
It had never occurred to me that Pius XII’s address to midwives gave the yellow light to the “quality of life” moral theology, but I clearly see it now.
This is the kind of thing which should never have been broadcast publicly, as it would certainly be taken as a general principle (and in former times would have been written in Latin only in theology manuals).
But for the reason stated above (ie., eugenic justifications), there is something at fault in the principles here, and not just the imprudence of having given such a public address.