I can remember my Pastor telling me years ago that he read a book that he wouldn't want someone else to see because of fear it could lead them away from the faith. While I understood his position, ultimately our faith rest in what the bible says and is not based on loose (no evidence) facts, but sound historical evidence as well as the natural world that screams God, in-spite of the atheist who says he can't see it. In other words, its important to me that my faith holds up no matter what is thrown at it and if something could ever truly prove I am wrong, then so be it. I don't want to be trapped in a cult like religion with no basis or fact-do you?
Thus, it is certainly scary what I see in these groups, but I've learned a few things as well. The faint of heart and easily swayed be warned for sure, but like I said above, if our faith is true, it will show itself biblically, historically and in this creation around us.