not a problem for Mormonism. “One true church” rhetoric notwithstanding, LDS theology confirms there is real and potent Light in many moral systems/religions if not all; indeed, God works with people where they are. Scriptures, in fact, is God working with people where they are (accommodation) — humans expressing their imperfect understanding of God, in specific ways that require scholarship and exegesis (joint with personal revelation) to uncover. They aren’t science books and we pervert their original intended meaning when we impose modern materialist eyes on to them in any way, shape, or form. Everything, including temple rites, are imperfect expressions of eternal truths. They’re the best we can do. That doesn’t invalidate those things as legitimately true (in sometimes ineffably trenchant ways), however.
But anyway, a lot of what Harris et al. beat down is classical theism and on the basis on fundamentalist assumptions. That’s not Mormonism.