Marla Swoffer is absolutely right: Mormonism is not authentic Christianity. Mormonism has never been deemed anything other than a cult by mainstream biblical and historic Christianity. For their part (until very recently) Mormons have always denied being mainstream Christians anyway. They claim true Christianity was totally lost and the church was dead until Christ began "the Restoration" under Joseph Smith.
The fact that lots of Mormon moms are likable, politically conservative women who homeschool their kids does not alter the seriousness of Mormonism's error. Mormon doctrine corrupts the very essence of biblical truth and the gospel itself, trading the simplicity of the apostolic gospel for a different message. See Galatians 1:8-9.
Christian homeschoolers need to guard diligently against allowing their movement to become just one more vehicle for the kind of ecumenism that surrenders vital distinctives of classic Christianity while making unholy alliances in the name of impacting the culture, upholding high moral standards, opposing secularism, or whatever.
As a matter of fact, Mormonism is a false religion that is every bit as spiritually deadly as the humanistic secularism most Christian homeschooling parents are trying to avoid.