when is a christian not a christian?

Is it just me or does the media seem reluctant to describe the "polygamist sect" down in Texas as Christians? The group in question, the Fundamentalist Church of Jesus Christ of Latter Day Saints, are a splinter group of the Mormon Church which decided to stay polygamous when the rest of the church decided to ban the practice.

Religious Tolerance: Fundamentalist Church of Jesus Christ of Latter Day Saints
Rick Ross' "Cult" Website: Polygamist Groups
Wikipedia: Polygamy
Biblicalpolygamy.com