Why do Mormons call non-members gentiles?

Members of the Church of Jesus Christ of Latter-day Saints (the "Mormon" church) are asked to refer to those outside of the church as "friends of other faiths" or "non-members." This is because the term 'Gentile' can be negative or alienating. However, historically and in scripture, non-Mormons have been called Gentiles, following the pattern of non-Jews being called Gentiles in The Bible. They do not mean this to be a derogatory term, it is just used as a title for those who are not Mormons.