Joseph Smith’s first vision tells us, speaking of other churches, “all their creeds were an abomination in his sight, that those professors were all corrupt.” (JS History 1:19)
Those of other churches often take this very personal. To them we are claiming their church is an abomination. But that is not what this says. Instead, it clearly states that their creeds were an abomination. This is really a huge difference. The creeds took away God’s fathership, but instead made him an essence, metaphysically combined with Jesus and the Holy Ghost. This altered the very nature of God, presenting Him as an unreachable entity rather than a personal Father, and often included unscriptural concepts. We are no longer his children, but simply made out of nothing. They outlawed a belief in a preexistence, baptism for the dead, and created fixed theological boundaries, which prevented ongoing revelation. This all caused widespread corruption, establishing false doctrines and created divisions that led people away from the gospel.
As for the corrupt professors, knowing Joseph’s history further tells us that these are the specific religious leaders that Joseph had communed with--not all religious professors.
But all this does not speak of the churches themselves. More specifically, the people of those churches.
Some revelations received before the church was organized are very telling. For examble, D & C 10:55, “Whosoever belongeth to my church need not fear, for such shall inherit the kingdom of heaven.” This was written before the LDS church was organized. It cannot refer only to LDS members as there were none.
Some will still bring up other scriptures to drive home the point of how we look badly on others.
“There are save two churches only; the one is the church of the Lamb of God, and the other is the church of the devil; wherefore, whoso belongeth not to the church of the Lamb of God belongeth to that great church, which is the mother of abominations.” (1 Nephi 14:10)
Assumptions must be made to make this scripture look as they wish. But Dallin H. Oaks, speaking on this very scripture, breaks it down for us. He tells us that “churches” here is not referring to institutional churches, but instead those who belong to the church of the Lamb of God, are “all who believe in God and seek to serve him according to their best understanding.” Clearly, many others not of our faith are included in “the church of the Lamb of God”. See here to see his talk and learn other points.
To take it even a step further, The Book of Mormon teaches us that non-members can be considered to be even more blessed than members. “The Lamanites… are more righteous than you. Their husbands love their wives, and their wives love their husbands; and their husbands and their wives love their children; and their unbelief and their hatred towards you is because of the iniquity of their fathers; wherefore, how much better are you than they, in the sight of your great Creator?” (Jacob 3:5)
Do others have hatred toward us? Or at least some form of enmity? Absolutely. I have witnessed it many times. But as is the case with the Lamanites, in most cases it is simply what they have been taught that they tightly hold onto. The Book of Mormon speaks on this. In 2 Nephi 10: 5 it tells us the main reason that has driven this enmity from the beginning, that even blinded people from the truth of Christ. “Because of priestcrafts and iniquities, they at Jerusalem will stiffen their necks against him, that he be crucified.” Here we learn that priestcrafts (paid clergy, and now paid social media) are often the ones driving this. In addition, the need to hold onto iniquities. This can be the need to hold onto beliefs such as easy believism and their incorrect assumption that we are a works-based church. Again, in The Book of Mormon we learn they are, “Humble followers of Christ; nevertheless, they are led, that in many instances they do err because they are taught by the precepts of men.” (2 Nephi 28: 14)
LDS membership can be seen as relatively demanding that many simply cannot commit to. We still very much want other followers of Christ to join with us, for there is more--much more. “I do not bring it (my gospel) to destroy that which they have received, but to build it up.” (D & C 10:52)