How is it still ordered to procreation?
The marital act is one of full acceptance and full giving. God designed the female body to be fertile at times, and infertile at others.
NFP accepts that, and therefore when each spouse gives themselves to the other, they are giving themselves exactly as God has made them. Nothing is being held back.
When the act is interupted by artiicial means, it is a rejections of the fertiltiy of the spouse. It is, in effect saying, I love you, except for your fertility. God erred in making you fertile at this time, therefore I will change that before I accept your gift or offer mine.
That is hardly a loving thing, to reject as aspect of your spouse that God created in your spouse as a full aspect of humanity.
It is akin to saying, I love you, and I want your gift of self, but I reject your face, so you must wear this bag over your face before I will share my gift of love with you and accept yours in return.
I can pretty much guarantee that if I tried that with my wife, I’d be sleeping on the couch for the next millenium. But couples think that saying the same thing in regards to their spouses fertility is somehow an act of love? I think not.
Fertility is a God given gift and a part of each spouse. NFP respects that and each spouse accepts that in the other EXACTLY as God has given it, no changes.
Artificial means do not, they are a bag over the face of your partners fertility.