Famous Mormons like Willard Marriott advertise the magical quality of Mormon garments on 60 minutes:
Mike Wallace: Do you wear the sacred undergarments?
Willard Marriott: Yes, I do. And I can tell you they do protect you from harm.
Mike Wallace: Really?
Willard Marriott: Uh-huh. I was in a very serious boat accident. Fire--boat was on fire, I was on fire. I was burned. My pants were burned right off of me. I was not burned above my knee. Where the garment was, I was not burned.
Mike Wallace: And you believe it was the sacred undergarments.
Willard Marriott: I do. Particularly on my legs, because my pants were gone, but my undergarments were not singed. ("60 Minutes" program on the LDS Church. Aired on CBS TV, April 7, 1996)
Church presidents tell the faithful that the garments have magical properties:
“Temple garments afford protection. I am sure one could go to extreme in worshiping the cloth of which the garment is made, but one could also go to the other extreme. Though generally I think our protection is a mental, spiritual, moral one, yet I am convinced that there could be and undoubtedly have been many cases where there has been, through faith, an actual physical protection, so we must not minimize that possibility” (The Teachings of Spencer W. Kimball).
For a garment made of cotton to protect people from fire and other physical dangers, it would defy physics, in other words the garments would take on a supernatural form, what some people would call magic. This was not made up by anti-mormons. This is a belief that comes from within the culture of Mormonism. Outsiders are simply learning about these beliefs and laughing. Mormons can either stand firm and confident behind the belief that garments offer supernatural protection from physical harm, or they can issue a statement, to be read to all members, that the garments are simply a reminder of the covenants made in the temple, and do not offer physical protection. They are trying to hold to a mmiddle ground where they tell members one thing, while trying to sound mainstream to the outside world. It never works.