These are some of the first things Mormons receive when they enter the temple for the first time. Following is how these garments are explained in a popular LDS Church manual.
“The garment provides a constant reminder of the covenants you have made in the temple. You should treat it with respect at all times. You should not expose it to the view of those who do not understand its significance, and you should not adjust it to accommodate different styles of clothing. When you wear it properly, it provides protection against temptation and evil. Wearing the garment is an outward expression of an inward commitment to follow the Savior”True to the Faith, p. 173
These undergarments have often been a source of ridicule on the part of non-Mormons. But, as the above quote illustrates, they are very important to Mormons. Making them objects of ridicule builds barriers and not bridges to Mormons.