This is simply not true.
Members of the Church of Jesus Christ of Latter-Day Saints believe the Bible to be the word of God as long as it is translated correctly. In the last couple centuries, the Bible has undergone a lot of editing. Translators often changed things that didn't agree with their personal beliefs and that has caused a lot of confusion amongst the different religious sects. In one site I found, it lists 121 different English version of the Bible. It's in interesting site. If you want to look at it. It shows when the different versions or translations were created.
In the process of translating, some errors are expected. Some are accidental, some are purposeful. Regardless, we are humans and we err. This is why the wording can be so different from Bible to Bible and why we become so confused. Which translation is correct?
We believe you can not possibly replace the Bible. It is the record of Christ's life among the Jews. His words are sacred and we are so grateful that his followers were able to preserve his words and deeds.
The Old Testament is equally important to us. We don't believe the stories in there are symbolic. We believe they truly occurred. God can do all things, and we believe there truly was a flood. We believe that Abraham, Isaac, and Jacob lived and did the things that the Old Testaments says they did. We love the Bible stories and doctrine.
Currently, we read the King James version. However, due to many of the translation errors, the version that our church distributes also has a Joseph Smith translation section were Joseph Smith cleared up some of the confusing mistakes that are prevalent through that version of the Bible. We believe that Joseph Smith was a prophet and that the Lord communicated through him to help us more fully understand the Bible.
Many people use the argument, "You can't have more scripture (talking about the Book of Mormon), because The Book of Revelation says that (Revelation 22:18-19) if anyone adds or takes away from this book, they shall be cursed." Many Christians assume those words are talking about the entire Bible. What they don't understand, is that originally, the Bible wasn't put together. It was originally just different books. The word Bible actually means "the books." It is only (relatively) recently that al these books were put together in one volume. If you look at John's actual words, he says:
18 For I testify unto every man that heareth the words of the prophecy of this book, If any man shall add unto these things, God shall add unto him the plagues that are written in this book:
John says, "book of this prophecy," meaning only The Revelation of St. John. In other words, if anyone changes the words purposefully, that is when the curse that he prophesies would come upon them.
We believe that the Bible and Book of Mormon together teach us about our Savior and clarify the confusing bits of the Bible. We love the Bible, but if you knew that the Savior had talked to someone else and they had written down the words that He said, wouldn't you want to read those words as well?
That is why we read the Book of Mormon. It is more of Christ's words to people on a different continent. God loves all his children, not just the Jews. He wants all of them to receive eternal life, and Christ is the Savior of all mankind. Thus, he has more for us to hear, if we will only listen.
As I read the Bible and Book of Mormon together, they both make more sense. The gospel becomes clear and I realize that God has not left us alone. He still is trying to speak to us today if only we have ears to hear.
We believe the Bible to be the word of God, as far as it is translated correctly; we also believe the Book of Mormon to be the word of God.