Again, my difficulty is not that I do not feel bound or agree with its teaching, but that the aftermath of Humanae Vitae seems to have been characterized by efforts to deny that it constitutes evidence for anything or that it poses a moral obligation on the left, and an attempt to suppress further examination of the issue on the right. That makes nonsense of Church teaching and the Bible as well. Catholics are required to hold infallible teachings as certain, that is, if they want to be Catholics. Greater insights and profounder study reinforce the truth already held as true and clarify what was not so clear before. I refer you to Newman's study on development of doctrine for your further investigation.
Artificial contraception is immoral.
The pill is immoral. The conclusion is equally constant as soon as the minor is established. They have no place in theological discourse. When we have heard the Church's teaching, we can play or we can leave the game. I wish you were either cold or hot.