Actually this is a big part of why you see so many successful mormon authors! Not necessarily people being deliberately pressured to buy the books, I've never heard of that happening, but there's a big writing culture and it's generally easier for mormons to get published in the first place because of their accessible English university classes and their internal book distribution network giving many authors a leg up. It's worth noting that while I'm unaware of any deliberate attempts to game bestseller lists like these tags imply, simply being mormon authors helps sell books to other mormons, because mormons tend to be very wary about reading inappropriate content. A mormon picking out a book for themselves, or especially picking out a book for their children, will likely favour a book available through their mormon bookstore or a book written by a mormon in a bookshop, because they know that the material in the book will be appropriate and morally acceptable. (That or Disney, which is al,so apparently very popular among mormons.) Since mormons tend to have a strong reading and writing culture, this captive audience certainly isn't nothing.