Purist fundamentalist Mormon? Like on that 'Missouri is the Biblical Eden of the Christians', 'The United States Government must be overthrown' and 'polygamy is an old man's game to keep women, the younger the better, and toss young men to the wolves/desert them' tip? That Purist Fundamentalist Mormon shyt?
Joseph Smith was a charlatan on the same level as L. Ron Hubbard, Wallace Fard and Oral Roberts (I'd mention Jim Jones, Marshall Applewhite and David Koresh, but those three actually believed the crack they were smoking). Hating on Roman Catholicism was easy, because everyone was doing it. Joe Smith sold snake oil, and changed up the recipe depending on what winds were blowing in popular politics.
See also: the bullshyt Egyptology translations, and his plagiarisms from a book of poorly sold fiction him and a friend had put out earlier. L. Ron looked at what Joe Smith wroth, and figured he could do him one better using the same basic blueprint. Ta daa.
You can't believe in what Joe Smith believed in, because he believed in nothing except commanding the rubes on some human Sandking trip. And when he died, it was his own damned fault. If I remember correctly, he stayed instigating, because he was so sure that his buddies would get him out of the bind he put himself in with his bullshyt -- just like they had before. They came too late. So his buddies really revved up the 'US Government is going to pay' bullshyt among the idiots, post-mortem.
So, unless you mean 'purist fundamentalist Mormon' as a synomym for 'old school troll'.....