Joanne was indeed a mainstream Mormon. She was raised in the mainstream Mormon Church. When she and her husband joined a polygamist cult, the mainstream Mormon Church excommunicated them.
But speaking of misleading, the rest of the writer’s comment is not entirely true. It is at best technically true. And as Bill Clinton reminded us, that which is “technically true” can be “designed to mislead.”
NOT ENTIRELY TRUE: “… [in] the LDS/Mormon church ... [the] practice was stopped over 120 years ago …”
FACT: The Mormon Church did not stop polygamy 120 years ago. In 1890, it declared an official end to polygamy, but unofficially looked the other way while allowing the practice to attrit over the next few decades. At the same time, the Mormon Church sent settlers to Mexico, where polygamy was not yet illegal, specifically to continue polygamy on an official basis there. Mitt Romney’s ancestors numbered among the original settlers.
FACT: Mainstream Mormons allow polygamy for widowers. A worthy Mormon widower can remarry and have both wives in heaven; should the second wife die, he can again remarry and have all three; and so forth. It doesn’t go both ways, however. Here and in the hereafter, Mormon women are limited to a grand total of one husband.
FACT: The Mormon Church stands by polygamy as a doctrine and a commandment from God. It defends the practice among early church members, reserving their condemnation of the practice to the here and now. They believe that God reserves the right to reinstate polygamy at any time.
NOT ENTIRELY TRUE: “… a fundamentalist sect [has] absolutely no connection with the mainstream Mormon church.”
FACT: It would be more accurate to say “… has no official connection.” Fundamentalist Mormon sects and the mainstream Mormon Church could hardly have a stronger doctrinal and historical connection. Mormon Church founder Joseph Smith introduced polygamy the year after the church's organization in 1830. The Mormon Church’s own book of scripture Doctrine and Covenants says that polygamy is a law, and that once it is revealed to you, you must obey it. Fundamentalist Mormon sects purport to have returned to the church’s roots (hence “fundamentalist”). On this one, the facts appear in their favor.
To be fair, the writer is likely more guilty of failing to think critically than of trying to mislead. The writer merely parroted the official stance of the Mormon Church. So ... just who is guilty of deception?