Not all of the wives were brought up with polygamy, and even those that were were exposed to the normal American culture and were free to not choose it so indoctrination doesn't really seem to fit in this case. Some of the polygamists are cultish with no access to outside information, no contact with the world outside of the cult. Those are the ones who marry the young girls, kick out the boys etc. but I don't see that being the case here at all.
Those cults also believe a man MUST be polygamous, but I don't think we've heard if that's what this group believes or not. In most cultures that practice polygamy it is a choice not a MUST and a low percentage actually practice it. When the Mormon church practiced it less than 2% of the population actually were involved in polygamous marriages. I can't remember the exact statistics for other cultures where it's practiced but it was about the same.
As I did my research I discovered that polygamy is not the picnic for men that some think it is and many men given the option don't choose it. That said I reiterate that I find Kody creepy and sceezy, but I don't think that means all men who choose to live polygamy in cultures where it is accepted choose it for lecherous and/or selfish reasons.