By some complex, convoluted rationalizations, some men have been able to convert their desire to have multiple sex partners... especially young ones, into superficially justified situations where they can live their fantasies.
I'm sure that most of them have told themselves "it's ok" enough times and in enough ways that they emotionally believe it. The trappings of religion are, and have always been, one of the easiest ways to convince impressionable women to join them. Often, the full implications of the influence of the 'church' are not apparent to the women/girls until after they are trapped and 'married' and/or pregnant.

It is too bad that it is so hard to prove that laws have been broken, but organizations like Warren Jeffs' are adept at hiding the truth AND intimidating those who might try to leave.

I hope this case is the beginning of the end for such groups, but I fear it will only change the methods for the next attempt to acquire a private harem.