In reality, most polygamist communities are authoritarian and push girls into marriage before they're old enough.
"Authoritarian" doesn't mean abusive; marriage of a girl under the age of 18 is in no way proof that she has been raped or abused. And, I assure you, there is no evidence whatsoever that any girl in the FLDS compound has been abused. Having a child before age 18 is not only not indicative of abuse, it's hardly uncommon. 36 out of every 1000 Texas girls under the age of 18 gives birth each year; nationally, it's only 21/1000.
The purpose of the article, though, is the legal status of polygamy; read up.