I have been wondering why, if contraception works, it is a big deal?
Since, therefore, the conjugal act is destined primarily by nature for the begetting of children, those who in exercising it deliberately frustrate its natural power and purpose sin against nature and commit a deed which is shameful and intrinsically vicious.
–Pope Pius XI, Casti Connubii, no. 54
Paul VI explains how this is different from so-called “natural birth control” in Humanae Vitae, no. 11-12.
Search the main Catholic Answers website - there is a good deal there I imagine and will be more developed then short Posts here.
You might also want to read this book, which details the adverse societal consequences of contraception.
Define "it works’.
I mean you could say robbery “works” to get money. Abortion “works” to get rid of an unwanted baby. Euthanasia “works” when grandma is a burden.
The fact that something “works” isn’t the foundation of morality of the chosen action.
Our sexual faculties were made by God with a specific purpose, ordered a particular way. We are not free to disrespect God and his design. We are not free to disorder the marital embrace.
Some contraception, like “the pill” is considered abortifacient. Also, it intereferes with God’s will. Further, it does not promote unity and procreation within the marital act.
Why would the effectiveness of an act have a bearing on its goodness? Clearly - it does not.