While we may not like this particular religion, that doesn't matter. They are a religious organization, and an organized religion. Especially in the United States, the government most certainly should not determine what is or is not a religion. It's stated pretty clearly here:
"Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof..."
Any religion will have aspects that people agree with and don't agree with. If their activity is outright illegal, then punish that specific activity. Christians can worship Christ. Muslims can worship Allah. Pastafarians can worship the Flying Spaghetti Monster. Satanists can worship Lucifer. Eco fairies can worship Mother Earth. Atheists can worship nothing. Democrats can worship government. Republicans can worship capitalism. And Scientologists can worship whatever it is they worship.
The minute we allow government to dictate what is or isn't a religion is the instant we lose all religious freedom.