Ironically, it is Fr. Pfeiffer in this old Angelus
Article who points out the common teaching of the Church: Baptism of desire is de fide
[Here is the link to entire article, in which additional Feeneyite errors are refuted: http://archives.sspx.org/miscellaneous/feeneyism/three_errors_of_feeneyites.htm
The doctrine of baptism of desire is optional
The Feeneyites present the Church’s doctrine of baptism of desire as a question to be freely discussed within the Church: "...what amounts to an academic difference to be settled by the Church." If this were the case, each school of thought would then have to be accepted until the pope later defined this doctrine. This is false. The error here is to claim that only that which has already been defined belongs to the deposit of Faith, and everything else is opened to free discussion. The truth is that one must believe everything which belongs to the deposit of Faith, that being what has already been defined and that which is not yet defined but is unanimously taught by the Church.
Such is the case for the doctrine on baptism of desire, by the Feeneyites’ own admission. They write: "This teaching [on the "three baptisms"] indeed was and is the common teaching of theologians since the early part of this millennium." However, this was not only the "common teaching of theologians," but also that of popes, Doctors of the Church, and saints! In addition, it is found even before this millennium in the very early years of the Church without a single dissenting voice.
Therefore one ought to believe in the doctrine of "three baptisms," as it belongs to the Catholic Faith, though not yet defined. That is why St. Alphonsus can say, as we have already reported: "It is de fide...."
We can concede that if a point of doctrine is not yet defined, one may be excused in case of ignorance or may be allowed to discuss some precisionwithin the doctrine. In the case of baptism of desire, for instance, we are allowed to discuss how explicit the Catholic Faith must be in one for baptism of desire. But one is not allowed to simply deny baptism of desire and reject the doctrine itself. Rigorism always tends to destroy the truth.
He who denies a point of doctrine of the Church, knowing that it is unanimously taught in the Tradition of the Church, even though it is not yet defined, is not without sin against the virtue of Faith "without which [Faith] no one ever was justified" (Denzinger, The Sources of Catholic Dogma, 799; hereafter abbreviated Dz).