I don't shy away from my belief Protestantism (esp. Reformed Protestantism) is a heresy and is Satanical to its core. See, for e.g.:
Not By Scripture Alone: A Latter-day Saint Refutation of Sola Scriptura
Response to a Recent Attempt to Defend Imputed Righteousness
I was rather pleased to see another Latter-day Saint (one who has read at least some of the writings of Luther et al [*]) come to similar conclusions:
After the Protestant Reformation
of the 16th century, the various Protestant churches were splintered
off from that great schism produced a wide range of creeds and “confessions”
whose main functions were to distinguish the many Protestant sects from one
another. They were often lengthy and elaborate affairs, and bore no resemblance
or relationship to the early Christian creeds, and cannot be properly regarded
as extensions, continuations, or developments of them. By the time of Joseph
Smith these Protestant declarations of faith had multiplied without number. The
following quote from the preface to the first edition of the Doctrine and
Covenants, published in 1835, shows that Joseph Smith was aware of this
phenomenon, and saw it as a problem: “There may be an aversion in the minds of
some against receiving anything purporting to be articles of religious faith, since
there are so many now extant; . . .” (emphasis added). Evidence suggests
that when Joseph Smith condemns the “creeds” of the churches, he is actually
referring to this welter of Protestant declarations, and not to the simple
creeds of the early Christian Church. (Bijhan Nasser-Faili, Essays on
Doctrine: Nine Articles Relating to the Doctrine of the Church of Jesus Christ of
Latter-day Saints [3d ed.; Antum Publications, 2020], 17)
The suggestion [one
LDS] author makes that the Protestant Reformers were “inspired by God,” and
that the work that they did resulted in a genuine “reformation” of the
Christian Church is also highly questionable. The Protestant Reformation was in
reality a heretical movement like the many others which had preceded it, and
its outcome for the Christian world was more disastrous than good. One of the
greatest mistakes that Latter-day saints have made during the past 170 years
has been their tacit endorsement of Protestantism, which has absolutely nothing
in common with the restored gospel, and which is utterly repugnant to it.
Joseph Smith identifies the Protestant Reformers as “traitors and apostles”:
The character of the
old churches have always been slandered by all apostates since the world began.
I testify again, as the Lord lives, God never will acknowledge any traitors or
apostates. Any man who will betray the Catholics will betray you; and if he
will betray me, he will betray you. (Teachings of the Prophet Joseph Smith,
375)
The reference to the
Protestant Reformers is obvious, as well as to the Evangelical churches at that
time who slandered both him as well as the Catholics.
Latter-day Saints,
with the wealth of knowledge gained through modern revelation, are in a
position to make an enormous contribution to the development of Christian
theology; but they have so far failed to take advantage of that great
opportunity because they have such a distorted notion of the historical
development of Christianity, and lack of appreciation for traditional Christian
theology. (Ibid., 45)