He again fairly accurately opines on the motives for trotting this gem out every year:
For many, I think it’s just a rather bitter and not particularly funny joke. Some, though, seem to take the claim seriously — or, at least, to want others to take it seriously.
But, you know, I have to say, this is all really sad. Imagine that you are a believing Mormon, and as a believer you think that the birth of the Prophet Joseph Smith heralded the opening of the Last Dispensation and the Restoration of the True Gospel of Jesus Christ. A figure who stands second to Christ himself in salvific significance. But the LDS Church gives very little attention to his birthday.
Why? I think we all know why. Because Mormons already catch enough grief regarding their veneration of Joseph Smith as it is. Mormons sing "Praise to the Man" to the tune of "Scotland the Brave" as a holy hymn, in other words, a musical prayer to God, in which it is noted:
Hail to the Prophet, ascended to heaven!
Traitors and tyrants now fight him in vain.
Mingling with Gods, he can plan for his brethren;
Death cannot conquer the hero again.
Here we see that Joseph Smith has been exalted and thus has become a god.
Great is his glory and endless his priesthood.
Ever and ever the keys he will hold.
Faithful and true, he will enter his kingdom,
Crowned in the midst of the prophets of old.
As a god he will enter his kingdom. His glory and priesthood are endless, as are those of Christ.
But, considering the topic at hand, also note that:
Praise to his mem'ry, he died as a martyr;
Honored and blest be his ever great name!
Long shall his blood, which was shed by assassins,
Plead unto heav'n while the earth lauds his fame.
Joseph Smith is a martyr, just as the ancient martyrs of the Christian faith.
So, Joseph is a saint, a martyr, and someone who has been exalted to mingle with the Gods. And Mormons sing a musical prayer that celebrates all of these things. They also believe that they must pass Joseph's scrutiny as they go through their divine judgment. In this sense he is like Minos, Rhadamanthys, and Aeacus, the Greek judges of the Underworld.
So why would Mormons not make a big deal out of celebrating his birth?
One might think of Smithmas as something like a Catholic Saint's Feast Day. Or Joseph might be remembered in the way that English Christians sing "Good King Wenceslas" on the Feast of Stephen, the day AFTER Christmas.
What could Mormons do? Well, December 23 is the Feast of Saint Thorlak, the patron saint of Iceland. The Feast of Saint Thorlak is considered the last day of preparations before Christmas, during which the house is cleaned and preparations for the Christmas meal are begun.
What might Mormons do to remember Joseph Smith on December 23rd? Well, singing "Praise to the Man" would be one option. Or perhaps a new song could be composed that would be more fitting for a celebration of the life, as opposed to the death, of Joseph Smith, similar to the way that King Wenceslas' virtuous deeds for the poor are celebrated in song on the Feast of Stephen.
So, maybe I am not advocating Smithmas exactly. It may be, however, that they could sing in prayer and celebration in remembrance of the birth and life of Joseph Smith on the Feast of Saint Thorlak, December 23rd.