In response to why, in one account of Joseph Smith's First Vision, Joseph would use "angels" to denote deity, Jeff Lindsay wrote:
Further,
the mention of angels instead of heavenly beings in some accounts is also
easily understood as a generalized term that encompasses all heavenly beings,
especially those that appear to mortals. When one sees two divine beings, they
can be called angels, even when they are God the Father and the Son. This usage
is actually Biblical, for Jacob in Genesis 48: 15,16 speaks of "God,
before whom my fathers Abraham and Isaac did walk, the God which fed me all my
life long unto this day" as "the Angel which
redeemed me from all evil." Why would Jacob call God an Angel? Because,
like Joseph Smith, he had seen God (see Gen. 48:3; Gen. 35:9;
Gen. 28: 11,12). That's the sort of thing that many prophets have experienced,
no matter how much our critics deny it. (Jeff Lindsay, LDS FAQ: Joseph Smith and His Accounts of the First Vision: Fatal Contradictions?)
Such was
common in the 19th century. John Garbett, an Anglican theologian and
minister, writing in 1827, while critiquing the Roman Catholic practice of the invocation
of angels (e.g., Gabriel; Michael), used the generic term “Angel” to denote the
person of Jesus Christ in premortality:
That the angel whom Jacob invoked to bless
his grandsons, was no created angel, but the Lord himself, the “Angel of the
covenant”, is implied in the terms of the invocation which is addressed to a
single personage: “God, before whom my fathers, Abraham and Isaac, did walk;
the God who fed me all my life long unto this day; the angel who redeemed me
from all evil; bless the lads.”—Is it not evident that the God before whom his
fathers walked, who had fed him during life, was the Angel who redeemed him
from all evil; even he who has been through every age the omnipresent Preserver
and Redeemer of his people.
This is the unanimous exposition of the
Hebrew and Catholic Church. “That Angel”, says the Rabbi, “is the Redeemer, who
is found in every redemption that is in the world:--the Shechinah, who always
walks with man, and never departs from him” (Quoted in Dr. J.P. Smith’s
Testimony to the Messiah, Vol. I, p. 345). And thus the champion of truth, St.
Athanasius, announces the orthodox opinion: “Jacob did not couple one of the
created natural angels with God who created them; nor, leaving “God who fed”
him, did he ask a blessing from an angel upon his grandsons; but by naming him “that
redeemed him from all evil”, he shewed that it was not any one of the created
angels, but the Word of God, whom he coupled with the Father, and prayed to
(Orat. 4. Cont. Arian). (John Garbett, The
Nullity of the Roman Faith; Being a Practical Refutation of the Doctrine of
Infallibility in a View of The Evidence and History of Certain Leading Tenets
of the Church of Rome [London: John Murray, 1827], 312-14)
In light of both the Bible and 19th-century understandings of the scope of the term "angel," there is nothing wrong with Joseph Smith having used the term in such an elastic manner as his own contemporaries did the same exact thing.