Yes, polygamy (and marriage of girls/boys under 18) is practiced in cultures all over the world - the difference is that in those countries it is both legal and socially/culturally accepted. That is NOT the case in the US. Here it remains ILLEGAL to have more than one wife/husband OR to MARRY or have SEX WITH A CHILD.
Frankly I could give a FLIP how many spiritual wives some weird yayhoo of a man has...so long as he is honest with ALL his "wives" about how many wives he has and they ALL are over 18 when he does the whole "celestial plural marriage" thing with them or they start a family. I don't believe a "spiritual wife" is entitled to ANY assistance either - she should be considered the same as a legal wife - so the "husband" has to be able to FULLY SUPPORT ALL of his WIVES AND CHILDREN himself. If they are going to embrace the idea of polygamy, then they should also have to embrace supporting their families - as in NO STATE OF FEDERAL MONEY or SERVICES - if they believe God intends them to have 7 wives and 60 children then surely "God will provide" the husband a job to support all of them.
If we want to STOP the cycle of abuse and child-brides I think the FLDS children should be required to attend an accredited public school or an accredited private school until they are 18 or graduate - NOT home schooling, but a school that maintains the STATE REQUIREMENTS for graduation. Right now, I can assure you the "home schooling" the children get IS NOT approved by the state and does NOT meet state educational requirements. The women "teaching" likely didn't graduate from HS themselves. Putting the children into a real educational environment, with certified teachers where religious training and chores CANNOT be a part of the curriculum, would prepare the children for ANY life they decide to live - within the FLDS or outside it. Nothing needs to change, - there can even be a dress code or a uniform that meets FLDS wardrobe requirements and Religious "training" and chores can continue - before and after school, on weekends and in the summer. THEN - If AFTER GRADUATING and turning 18 the children wish to be polygamous - well great, but they won't be doing it out of ignorance with no education or knowledge of the world outside the FLDS.
My Opinion