Honestly might create a lot of friction if someone starts quoting the Book of Mormon in posts or cites the Pope as God's spokesman on Earth.
Well, that's exactly the point.
If someone quoted the Book of Mormon as authoritative in a general board or chat, yes, I could see how that might cause some friction, as it seems to me as well that a majority of members here are not LDS, and would find that heretical. However, wouldn't it be the loving and, well,
Christian thing to do, to create a space for people who identify as LDS to be able to discuss the Book of Mormon with each other without being questioned, or even harassed, by non-LDS people?
Likewise, personally I don't put anything a Pope said to be on equal footing to the Bible, in general. But I believe that Catholics have the right to trust their Pope's words and to take them as authoritative for them. I think they might appreciate having a forum to discuss Papal encyclicals, and having a space set aside, apart from general discussions where people might not be accepting of such things, makes a heck of a lot of sense to me.
If you don't think that should be allowed here, then maybe you should suggest changing the name of this site to "Evangelical Chat" instead of "Christian Chat."