In my personal experience becoming an LDS church member was like being a Christian on steroids! The LDS does follow the King James version of the Bible, in addition to the Book of Mormon, The Pearl of Great Price, and The Doctorine and Covenants. (The latter book is the one with the Law of Chastity IIRC).
There is one more "higher standard" that Travis held in his church that Jodi did not. He was a "Priesthood holder" - something Jodi could never attain. No female has been allowed this opportunity in the history of the church but people (men) of color became allowed to attain in the late 1970's.
I do agree with you that it is a slimy way to destroy Travis. I think the thing that is even slimmier (sic?) is that the DT is placing doubts in his family member's minds of Travis' chances for eternal salvation. That is what breaks my heart the most. This defense and Jodi is all about hurting Travis and his family, not only in ths life - but also the afterlife.