And this is, to be blunt, one of the most absurd and ridiculous "positions" I have ever read.  You are deliberately and dishonestly conflating the formal motive of the action with the objective action itself.  This shows your desperation to justify this sinful activity, and you commit grave sin by promoting grave sin publicly.  ALL of the Catholic moral theology regarding human sɛҳuąƖity is related to the ends of marriage, the primary and the secondary, and the need for these to be in proper order.  This goes all the way back to the Church Fathers, and you're throwing that all out claiming that there's nothing to it so long as the act is performed naturally, then motives have absolutely nothing to do with it.  You're undermining all of Catholic moral theology by making this claim, and you're making yourself into a fool.

It is a matter of fact-- not opinion-- that the Holy Offices of Pope Pius IX (1853), Pope Leo XIII (1880), Pope Pius XI (1932), and of course Pope Pius XII, all taught that periodic continence can be lawful.  It is also a matter of fact-- not opinion-- that during that hundred year period (1853-Pius XII), theologians unanimously agreed on its intrinsic lawfulness (although they did disagree on some of the upstream principles and downstream applications).  It is also a matter of fact-- not opinion-- that theologians were never rebuked for believing it to be a lawful practice.
.
Given the facts, I would agree that the Church infallibly teaches that periodic continence can be lawful to use.  The alternative is to suppose that a hundred years worth of popes and theologians universally erred on the matter.  Let's keep in mind who those popes are-- not just Pius XII (as it is so often ignorantly alleged), but Pope Pius IX and Pope Leo XIII.  Pope St. Pius X, a militant pope on moral and doctrinal matters, did not censure or rebuke theologians for teaching it.  Pope Pius XI is included among these popes as well (which should give anyone who thinks that Casti Connubii denies the lawfulness of periodic continence pause, since no sooner was the ink dry on that encyclical than did the same pope explicitly confirm its lawfulness via the Holy Office).  The scope of periodic continence being taught exceeds the scope of religious liberty being taught both in time and space.  
.
Of course, it is one thing to simply reserve judgment on whether or not this amounts to infallible teaching; it is another thing altogether to accuse such orthodox men, over such a long period of time, as having taught grave or even heretical moral theology.  
.
Importantly, I should point out that an expression like "the Church teaches periodic continence" should be understood to simply mean that the Church teaches it can be lawful to use.  The Novus Ordo seems by all accounts to teach something very different, they seem to teach that it ought to be used in some general away.  The Catholic Church has never taught that, she has merely taught that there is nothing intrinsically evil about it, and regularly warned that it is something that should be taken seriously, not taught (as a method) publicly or indiscriminately, and only used when there is a commensurate reason.
.

.
You don't need to try harder to convince me or anyone else that you feel strongly about the issue, you need to try harder to convince me and others that we should believe Casti Connubii makes the distinction you say it does after I have made an argument to the contrary.  What are your (non-question begging and commensurately responsive) reasons for thinking this is the case?  Check the link I gave you if you need to refresh your memory.  Right now you're just picking up on the emotional hand wringing and zealous platitudes you left off with a year ago.
.

By way of analogy against the false principles of Mith, there's no such thing as a sin of gluttony ... except if one were to eat unnatural/undigestible objects.

Since putting food into my mouth is a natural action, so long as I put the food into my mouth, and it digests, and goes through my digestive tract in the natural matter, there's no such thing as the sin of gluttony.  I can stuff cake into my mouth for an hour straight, all the while yielding to the intense passion to keep consuming sweets, and there's no sin so long as I don't throw it all up.  That's ludicrous, and it's precisely what Mith is proposing in his desperation to condone the gravely sinful practice of NFP.

And this is, to be blunt, one of the most absurd and ridiculous "positions" I have ever read.  You are deliberately and dishonestly conflating the formal motive of the action with the objective action itself.  This shows your desperation to justify this sinful activity, and you commit grave sin by promoting grave sin publicly.  ALL of the Catholic moral theology regarding human sɛҳuąƖity is related to the ends of marriage, the primary and the secondary, and the need for these to be in proper order.  This goes all the way back to the Church Fathers, and you're throwing that all out claiming that there's nothing to it so long as the act is performed naturally, then motives have absolutely nothing to do with it.  You're undermining all of Catholic moral theology by making this claim, and you're making yourself into a fool.  You also distort Vermeersch.  He was writing that the action is not objectively vitiated by the formal end, which is nothing more than making a distinction between principle #1 (the objective natural force of the act) and #2 (the formal intent).  EVERY moral theological approach to a given question takes into account not only the intrinsic nature of the act but also of the formal motive behind the act.  Acts can be objectively good or neutral but vitiated by intention, or objectively bad but not sinful due to intention.  So there's a distinction between the objective nature of the act and its morality due to the formal motive, which is why Vermeersch says "necessarily".

Not to mention, you may want to think again before publicly encouraging grave sin ... since with every post you are endangering your eternal salvation.

.
None of the popes nor theologians who taught that PC was lawful conditioned its lawfulness on its consequences.

Here we go again:
Loudestmouth gets argued into a corner, and starts accusing his opponents of dishonesty (his own psychological projection), dishonest motives, and all the rest.
Typical.
Habitual.

.
None of the popes nor theologians who taught that PC was lawful conditioned its lawfulness on its consequences.