I know a couple of LDS folks and IIRC, the Saints didn't even START practicing polygamy until AFTER they got to Utah.
Actually we (I saw "we" being Mormon and having ancestors who were involved in this portion of history) began practicing it before the murder of Joseph Smith and the subsequent exodus west to escape persecution. For a more precise history, see:
http://ldsfaq.byu.edu/emmain.asp?number=145
Why the heck would any man want more than one wife?
Believe it or not, Brigham Young himself thought the same thing when he first heard of the doctrine: "I felt to envy the corpse in a funeral cortege and "could hardly get over it for a long time" (Journal of Discourses Ch3 Pg266).
Also, even when practiced, it was not like you see being practiced by so-called "fundamentalists" today. Both men
and women entered into marriage voluntarily.
But as mentioned, we believe that after having restored the doctrine in the last days, the Lord commanded that polygamy no longer be practiced. Since that time, all members of the church found to practice or promote the current practice are summarily excommunicated.
These who force children, young girls, or anyone into these kinds of arrangments will have to answer to God. I agree with SMLE, that any indications of abuse should be investigated, the perpetrators fairly tried, and punished if found to be guilty. We Mormons have a natural distaste for "mob 'justice,'" for obvious historical reasons. Or at least we should, unfortunately there are those that forget the lessons of history.