Jacob Weisberg writes that he will not be voting for Mitt Romney because Romney is a Mormon, and then tries to explain why this position is not religious bigotry. In essence, he says that it's OK to oppose Mormons (and Scientologists) because these religions are recent and have not moderated themselves, as other religions have. He mentions Christianity and Judaism as examples of the latter. (It's not clear how he would classify Islam). He does make clear that he would not vote for Christian and Jewish fanatics, but his position appears to be that virtually all Mormons are fanatics. He leaves open the possibility that Romney might be acceptable if he would distance himself from church doctrine.
This position strikes me as one of ignorance. Specifically, ignorance of Mormons (and Scientologists). He doesn't know any, but from what he has read they are quite crazy and radical, and he wants no part of them unless they affirmatively refute the extreme positions he has heard about.
Furthermore, this distinction between older, moderate religions and modern, extreme ones strikes me as ridiculous. It could be argued that the older religions are more fanatical because they have been carrying out the same sorts of rituals and maintaining the same beliefs for thousands of years.