It's true that the mainstream LDS church has "excommunicated" the Fundamentalist LDS "church", but after having lived in Utah for more than four years, smack yourself if you think that polygamy isn't at least tolerated in Utah. I've seen plenty of examples of it to know better.
The difference here is that a TEXAS jury convicted this scumbag, who has been running from prosecution at least as long as I've been away from Utah. Furthermore, the victims are underage. Prosecutors won't even bother to prosecute someone for polygamy, which is also illegal. But once you interject the underage element, those prosecutors' ears perk up.
Get yourself a jury in Utah and in northern AZ and it could be a completely different result.