Why is a discussion of religious belief off limits? Why are these beliefs immune from rational discussion? If someone where to expound on the virtues of channeling dead relatives, you can be assured the ridicule would essentially bar them from holding elected office. Similarly if someone believes the world is flat that would also disqualify them from holding office. However, the beliefs of a man who aspires to the highest office in the land are danced around as if questioning them violated our highest laws.
For instance, Mormons believe that Joe Smith, their founder, used "Seer Stones" to receive a revelation from god. Well, many others who lived during he era also used seer stones... and other such nonsense.. in scams designed to separate farmers and other folks from their money. In fact, Joe himself used the same stones as a "money digger" before 'god' decided to redirect his enterprise:
In the early Latter Day Saint movement, seer stones were used as method of divination and played a significant role in its history and theology. Joseph Smith, Jr., the founder of the Church of Jesus Christ of Latter Day Saints, owned several seer stones from his earlier career as a "money digger."  Other early Mormons such as Hiram Page, David Whitmer and Jacob Whitmer also owned seer stones.  Seer stones are mentioned in the Book of Mormon and in other Latter Day Saint scriptures. James Strang, who claimed to be Joseph Smith's designated successor, also unearthed what he said were ancient metal plates and translated them using seer stones.
What people believe matters. If they believe fantastic things about our universe they should be questioned on it.