I don't mind an honest inquisition or comments into my belief system, but to publicly say, "Don't vote for Romney. He's a member of a cult. We can't have any non-Christians in the White House," is pretty out of bounds in my mind.
Allow me to clarify your comment, and know that because you put things so nicely, I am not offended at all by what you have said.
Mormonism is definitely different from most of Christianity, so I don't mind you calling it "its own thing" (by the way, no apostrophe needed there, wink wink).
Jesus coming to America is not a different interpretation of Jesus, it's (with apostrophe) just an additional something that we believe Jesus did, in addition to all the same stuff most Christians accept (remember, we believe in the Bible as well). The unique interpretation that I believe infuriates most "mainstream" Christians is the belief that the Trinity does not represent different aspects of a single Deity, but rather three separate Deities who are perfectly united as one. A Jesus who is separate from the Father is considered heretical in spite of historical precedent, biblical/linguistic evidence, etc. Thus, Mormons believe in a "different Jesus" and are not true Christians. I can understand this distinction far more than the "coming to America" bit, but still, we believe in a divine Christ who did all the same things that other Christians believe, so why exclude us based on a different definition of aspects of his nature? What if we are absolutely correct on the nature of Christ (after all, we claim our information came by revelation from God and not through philosophical debate after debate over hundreds of years and various ecumenical councils)? I still wouldn't feel right excluduing everyone else from the enviable Christian label.
As for Joseph Smith's character, the convenient absence (not loss) of the Book of Mormon source material, I will not delve too deeply into the topic at present (though I would love to, perhaps at a later time, maybe in a unique thread), I will say that the 11 other witnesses who saw the golden tablets all died without ever denying its actuality, though the majority were estranged from the Church and even bitter against Joseph Smith at some point of their lives, even up to the deaths of several. The Bible's manuscripts may be compared for its various discrepencies and alternate readings, as may the Qu'ran and other religious texts. The evidence of the existence of many artifacts, structures, or political situations is valuable, but many anthropologists discount much of the biblical narrative because they don't believe they are supported with real evidence. Ultimately, you still have to take certain aspects of your belief system on faith, and the difference between a "traditional" Christian's evidence and the evidence of a Mormon Christian is the timeframe we are investigating and questioning.