Yes, and yes. Firstly, the act of observation is surely an act. It is an act of learning something that is reality. God has never ordained the act of learning to be a sin. However, what we do with that learning can be.
Next, we move onto the ‘rejection’ of intercourse. This is not inherently immoral. If it was, the Gospels would not suggest it for couples, but they do suggest periodic abstinence.
So, the act of NFP cannot be inherently immoral, if it was, then learning and/or abstinence would be inherently immoral, but we know they are not.
What can then be immoral? The INTENTION for which NFP is used may be immoral. But not all intentions with respect to NFP are immoral. The catechism teaches us that.
Humanae vitae did say the ends and means must also be considered. Well the ends are a chosen sterility.
You are using ‘sterility’ in a fashion that the dictionary and the catechism does not. Here is the definition: Incapable of producing offspring. There is no act of NFP that produces sterility. The couple is still capable of producing offspring, therefore they are not sterile. By the way, most Artificial Birth Control DOES have the effect of making a couple sterile.
I cant see how the rectify this by in the same reading saying well the means are natural so it ok.
You are very perceptive about the means and the ends. So many don’t get this. But in this case, since the acts (means) of NFP are not inherently immoral, they do not need to be justified. That is what is meant by “the ends cannot justify the means”. The means must be considered unjust, to have to be justified. These means (acts) are not unjustified.
Howver, all intents must be justified. If you turn your search upon the intents, this subject will become more clear.
Are you also not rejecting the womans fertility and embracing only her sterility?
Again, the couple is NOT sterile, to purposely make either of them so would be a sin. Perhaps you mean that a couple practicing NFP is embracing her natural infertile time?
Would not true abstince be waiting five years to have sex? That takes real self control. Not two weeks.
I am not sure of your point. Abstinence, for proper reasons, and with full consent of both spouses, can be a good thing. However, it is not required.
Also what is the purpose of this embrace it is not to have children. The early church disagreed on the magnitude from mortal to veinal but they all considered sex without the desire to have children a sin. How does the church now say this is not a sin?
The Church says the intent to marry and the intent to never have children is hypocrytical, and is sin. The Church has never said that each individual sexual act must be done with the intent to create a child.