The first quote is saying that all sins sever a man from the Body of the Church, but due to their nature, none sever as fully as heresy or apostasy. He is saying that heresy and apostasy are the worst sins that exist.  

So your attempt at a refutation consists of saying that the words quoted mean the exact opposite of what they say? Interesting. Show in the quote where it says that "all sins sever a man from the Body of the Church".

I see the distinction, Trent's catechism explains it wonderfully:

"Heretics and schismatics are excluded from the Church, because they have separated from her and belong to her only as deserters belong to the army from which they have deserted. It is not, however, to be denied that they are still subject to the jurisdiction of the Church, inasmuch as they may be called before her tribunals, punished and anathematised."

Heresy and schism are mortal sins and all anyone who severed themself from the Catholic faith and who fell into those sins, and who is guilty of those sins, and who wishes to be absolved of those sins and rejoin the faithful has to do, is to walk into the confessional and confess their sins to a priest. You know, the same things only Catholics can do.  

You're still not right. You continue to interpret this quote with the exact opposite meaning of the words, contrary to every Catholic who has ever spoken on this topic besides the Wathen/Stubbornites.
The nature of other sins, committed by Catholics, do not sever one from the Church. Schism, Heresy and Apostasy do. I don't know if you are doing this on purpose but I do know we have this argument every once in a while and you always interpret this wrong. Malice must be presumed because the words couldn't be any clearer and your explanation couldn't be more wrong; since it is the exact opposite of the words of Mystici Corporis.

Well, I don't necessarily presume malice directly, I presume you interpreting it wrong either to adhere like gorilla glue to your sedeism, or because you adhere like gorilla glue to your sedeism - it's my opinion to be latter.

It is true that the nature of other sins do not sever from the Church like schism, heresy or apostasy, but what you fail to accept is that other sins do in fact, as Pope Pius XII said, sever us from the Church.

The adulterer can no longer receive absolution even though he may want it with all his heart, because he has severed himself from the Church with his adultery. St. Paul tells us that adulterers must not even be named among us Catholics.

The only way an adulterer can hope for forgiveness is to first abandon his adulterous life. The difference between him and the heretic/apostate/schismatic is their sin - or perhaps more properly said, the nature of their sin, of which I presume needs no further explanation.

As Pope Pius XII alluded to, both sins sever, but it is the nature of the sins that determine the gravity, hence the chances of the person wanting to seek forgiveness. No other sins severs one from the Church as does heresy/schism (sedeism)/apostasy, hence no other sin keeps one from seeking forgiveness as heresy/schism (sedeism)/apostasy. This is the meaning of Pope Pius XII's quote.
  

"The adulterer can no longer receive absolution even though he may want it with all his heart, because he has severed himself from the Church with his adultery. St. Paul tells us that adulterers must not even be named among us Catholics."

Could you give the cite, regarding St. Paul?

Why do you ignore ipso facto excommunications?  I do not understand you.

But fornication, and all uncleanness, or covetousness, let it not so much as be named among you, as becometh saints....For know you this and understand, that no fornicator, or unclean, or covetous person (which is a serving of idols), hath inheritance in the kingdom of Christ and of God.- Eph 5:3-5



I do not ignore anything, I merely accept the fact that it is not our place nor within our right to declare with any authority whatsoever that one is excommunicated from the Church, even though the censure is ipso facto.