(This is going to take two posts.)
Truth, thank you for posting this. I’m really quite relieved that you have asked for a second opinion on these things.
The LDS have "official teaching" manuals for the teaching of their beliefs. They can be easily found online with a simple google search. Here are a couple of points:
It appears as if your Catholic source has attempted to paraphrase his/her understanding of our doctrines, and quite frankly, hasn’t done a very good job. Included in this essay are numerous misleading statements and a few outright falsehoods. (I won’t go so far as to call them “lies,” since I believe a lie to be an intentionally inaccurate statement and I don’t know how much the individual who posted this information actually knows about the Church of Jesus Christ of Latter-day Saints. But they definitely are “falsehoods.”)
The Bible
Catholics & Christians believe the bible is the word of God. While Catholics retain 7 more books of the bible that were taken out after the reformation, all still believe the bible is the word of God.
The LDS say the bible is true as far as correctly translated leaving room for them to change it in a way that supports their belief system. They also created other "scripture" such as the Book of Mormon. They believe their "scripture" is just as important as the bible.
Yes, we do believe the Bible to be the word of God “as far as it is translated correctly.” Why would anyone want to be bound by a mistranslation? The writings found in the Bible were recorded, safeguarded, transcribed, translated and compiled over many centuries by well-meaning but fallible human beings. It would be extremely naïve to assume that it is a perfect record. Furthermore, the Bible that even the Catholic Church uses today does not contain all of the same books that were part of the Christian canon in the earliest centuries after Christ. Numerous changes (with respect to which specific books have been considered canonical) have been made over the years.
The fact that we believe the Bible to be incomplete and undoubtedly imperfect does not mean that we do not hold it in the highest regard. In our adult Sunday School classes, we study it every two years out of four. The other two years are dedicated to study of The Book of Mormon and The Doctrine and Covenants. And when we are studying it, we are studying it to learn God’s word, not to pick it apart or to try to figure out which passages
may have been “translated incorrectly.” We use the King James Version of the Bible, containing exactly the same text as the KJV Bibles used by any Protestant churches. Furthermore, we
never, ever, ever “change the Bible in a way that supports our belief system.” The text of our 2016 Bible is exactly the same as the text of our 1830 Bible was. (That’s the first example I found of a flat out inaccurate statement, and not merely a misleading one.)
And yes, we do believe our “scripture” is just as important as the Bible. Why shouldn’t anything that God has said be valued to the same extent as something else He has said? Why must all writings be contained within the cover of a single book in order to be equally valuable?
Marriage
The LDS still believe in polygamy. While many of the mainstream LDS don't practice it on earth (although many sects do) they believe marriage is eternal. For a man to earn a higher place in heaven he needs more than one wife. But this belief is completely different for women. A man can be "sealed" to several women on earth if widowed or divorced, but a woman may only be sealed to one man. Single women or female children who pass away before being able to married or "sealed" are assigned to men in their version of heaven. For those who are adults and unmarried there is a certain less than attitude among others.
Wow. Where do I even begin? At the beginning, I guess. We still do believe in polygamy as a principle. If two or three women were consensually married the same man here on earth and those marriages were performed by someone holding the proper authority, those women will all be married to that man in Heaven. I’m grateful that this is the case; if it were not, my great-grandmother would suddenly find herself husbandless, since she was his second wife. Yes, we do believe it is God’s intention that our marriages be eternal. As we are told in Ecclesiastes, “I know that, whatsoever God doeth, it shall be forever.” If a couple is married by the power of God, there is no reason to assume that God will dissolve that marriage in the next life. As far as “many of the mainstream LDS [not still practicing polygamy],” goes, I can’t speak to the intention of the writer, but the phrasing suggestions that while many don’t practice it, many others do. This, of course, is categorically false. Plural marriage is an excommunicable offense in the Church of Jesus Christ of Latter-day Saints. There are no ifs, ands, or buts. No extenuating circumstances.
Here's one thought for you to consider... Do you believe that Lutheranism is a Catholic sect? Probably not. The Lutheran Church, as well as all other Protestant Churches, broke off from the Catholic Church, but once they did, they were not "a Catholic sect." They were merely a Church that can historically be tied to Catholicism but is not considered by anyone today to be "a Catholic sect." The exact same thing is true with respect to the FLDS and other splinter groups that split from The Church of Jesus Christ of Latter-day Saints. These can historically be tied to us, but they are in no way a part of us today.
If we truly believed that “for a man to earn a higher place in heaven, he needs more than one wife,” neither Thomas Monson nor Gordon Hinckley, nor the vast majority of latter-day prophets and apostles could look forward to being "in a higher place in Heaven." We’d be saying that Abraham and Isaac would make it, but not Peter or Paul. That’s ridiculous. Why would we teach that a man needs more than one wife to earn the highest place in Heaven and then excommunicate any man who takes a second wife? I don’t think the writer of this post thought that one through very carefully. Furthermore, nobody is simply going to be “assigned” a spouse in Heaven. That’s not how God works. Besides, we are told in the Bible that no one will either “marry or be given in marriage” in Heaven. Marriage is an earthly sacrament/ordinance. (Note: The Bible does not say that no one will “be married” in Heaven, only that marriages will not be performed there.)
As Christians we believe marriage is a vital sacrament for those called to marriage and also recognizes that not everyone is called to married life even if they are not called to a religious vocation. We believe marriage is intended for our lives on earth and when a spouse passes away the living may remarry if they choose. (Aside from Permanent Deacons) But married or single our ability to go to heaven is not based on someone else's status within the church.
That is the case with Mormons, too. Married or single, our ability to go to Heaven is not based on someone else’s status within the Church.