Utah is a Mormon state: statewide, Mormons account for nearly 62% of Utah's 3.1 million residents [1] and 91 of the 104 state legislators are Mormon [2].
The LDS teachings are against pornography (comparing it to the plague in the very first line of [3]), and a survey of 192 male Mormon college students aged 18-27 showed 100% of them considered viewing pornography "unacceptable". [4]
That Utah would pass anti-pornography bills isn't surprising, IMO.