As a Mormon, Mitt Romney has a potential problem with some voters, particularly evangelical Christians, many of whom see Mormonism as a cult with nutty beliefs. This idea is fairly common, but you don't often see this kind of outright mockery on a news program via Ben Smith):
Obviously, the tone is totally unnecessary (apparently this "reporter" is a conservative radio host). And the reason so many people perceive Mormon beliefs as weird is that we haven't been marinated in them since birth. When you hear that in 1827 in upstate New York, God delivered to Joseph Smith some golden plates on which was written holy scriptures, you probably say, "That's ridiculous." But the idea that God delivered stone tablets to Moses on Mount Sinai is less ridiculous...why? Because it supposedly happened a long time ago? Mormons wear ceremonial undergarments? Crazy! Observant Jewish men wear a little cap? Totally reasonable!
On the other hand, if we're going to accept that all of a potential president's beliefs are matters of public concern -- beliefs not only about public policy but about culture, child-rearing, theology, and anything else you could think of -- then they have to take responsibility for what they believe. The last candidate I can remember who said his religious beliefs were nobody's business was Bill Bradley, but everyone else running claims to be strongly religious (the exception this year is actually the other Mormon, Jon Huntsman, who says he's not "overly religious"). If that's the case, then they ought to be prepared to answer questions about their faith.
Not that they will. I'm sure Romney will answer any questions about Mormonism by saying that what's important is his strong faith in God, and let's not get bogged down in the details. This is much like the Church of Latter-Day Saints itself, which, as Ben mentions, has been doing an absolutely brilliant PR job of late, mostly through restraint. They didn't complain about "The Book of Mormon," the smash Broadway musical (whose basic message is, yes, Mormonism is kind of nuts, but if it makes them into nice people, what's the harm). They've been promoting their religion in vague ways that have mostly to do with talking about how nice they all are. Go to Mormon.org and you'll see that the focus is on the people, not the theology -- the picture on the front page is a totally X-treme Mormon dude, rock-climbing with the prosthetic leg he designed himself. Ask a representative of the church why black people were disfavored by God until 1978 and were therefore not allowed to become Mormons, whereupon God changed his mind, and the representative will be likely to reply, "Hey, could that Steve Young throw a great spiral or what?"