Here's the difference: we are at war with Islam (whether Western governments choose to admit it or not). Therefore any indication that an American official may be a closet Muslim also indicates that he would be a closet traitor, because a Muslim may not take the side of infidels against fellow Muslims.
Conversely, I don't see how being a Mormon would lead one into treason against the United States. Perhaps you could explain some scenarios if you disagree?
Well, Mormonism has been "at war" with Christianity for the past 180 plus years, whether GoP voters want to concede that or not.
You see, when you call yourself a "restoration" -- and claim all Christian sects are part of some universal apostasy -- that's a basic "scorched earth" approach to the labeling of worldwide Christianity and all of the Christians that encompasses. That was Joseph Smith's approach -- to attempt a massive spiritual graveyard that would "bury" Christianity.
...because a Muslim may not take the side of infidels against fellow Muslims.
You do realize, don't you that Mormonism and Islam are on the same page in numerous theological ways -- one of which surrounds the use of that word "infidel"?
Muslims deem all Christians as "infidels"...Official Mormonism deems all Christians as "apostates."
Why Joseph Smith Ran for President
“I would not have suffered my name to have been used by my friends on anywise as President of the United States, or candidate for that office,
if I and my friends could have had the privilege of enjoying our religious and civil rights as American citizens, even those rights which the Constitution guarantees unto all her citizens alike.
But this as a people we have been denied from the beginning. Persecution has rolled upon our heads from time to time, from portions of the United States, like peals of thunder, because of our religion; and no portion of the Government as yet has stepped forward for our relief.
And in view of these things, I feel it to be my right and privilege to obtain what influence and power I can, lawfully, in the United States, for the protection of injured innocence.”
Joseph Smith, History of the Church, 6:210–11.