Or, in this case, Pope Paul VI properly maintained the fence on all 4 sides, and placed a lock on the gate in front.
Now, it is proposed to remove the fence on 3 sides, remove the gate, and then explain to the world how you are still protected by the fence.
Paul VI merely restated eternal Truth, previously made clear by Pius XI’s Casti conubii, to the consternation of those who were already convinced that he would (or, rather, could) somehow “change” Christ’s teaching on contraception.
Given his well-known predilection for Modernism, this came as rather a shock to those who already had decided for themselves that it was legitimate and moral.