I didn't intend to imply that. It was the source that made me wonder, with the presentation of information two generations out of date.
Your point is absolutely correct: NFP is free, healthy, environmentally-sound. Methods are very effective for not-conceiving, if practiced according to the instructions, and for helping with conception.
However, I believe it was Mother Teresa who observed that many couples do not love one another enough to practice NFP, which generally involves self-denial at times if the couple wishes to avoid conceiving.
You have a point. Said another way:
"The Christian ideal has not been tried and found wanting. It has been found difficult and left untried." - G. K. Chesterton