To me, this is a very compelling argument against the praxis of SS, the very one that I have used in the past. Certainly the Roman approach creates a sense of peace for some who have trouble dealing with disputes of this nature.
I have seen Calvinists call Arminians heretics over such disagreements. Each brand of Christianity seems to make their pet doctrines the most important ones for some reason. Pentecostals make healing and speaking the tongues very important. Calvinists defend the 5 points, Baptists defend believers baptism with all their might, and eternal security comes in a close second.
David Currie, a Catholic convert points out what he calls the five levels of truth in Catholicism, the idea of the Deposit of Faith, Dogma, Doctrine, Discipline and Devotion. I assume that we are familiar with what these mean, so no need to explain there further. The only two the Catholics must be united on without any disagreement are Deposit and Dogma. The rest there is room for dispute. Even on Doctrine.
Soul Sleep, Total Depravity, OSAS, the Rapture, Predestination would all fall under the category of Doctrine for Protestants (some would rabidly defende them as if they are part of the Gospel, but they are not). They amount to interpretations of what the Bible teaches. It teaches that we are predestined for salvation in Christ. Calvinism is an interpretation of what that means, as is Arminianism. One is probably more true than the other, but there is room for disagreement in the body of Christ about these things.
The Trinity and Abortion, Homosexuality and ABC are different. The last three relate to morality of living. Abortion and Homosexuality are clearly taught against in the Bible, even if others will misuse the pages of scripture to say otherwise. Failure to submit to its teaching does not mean its authority is invalidated. I mean Catholics say we Protestants fail to submit to the authority of tradition and what scripture witnesses about the church, but that does not make those things any less true in the eyes of Catholics, does it?