I see no reason why any organised religion should be exempt from paying their due taxes. Here's a chance to rob the mormon church of their tax exempt status...
Please visit http://www.thepetitionsite.com/1/review-the-501c3-status-of-the-church-of-latter-day-saints-the-mormons and sign it and pass it on to your friends.
The LDS church contributed a significant amount of money and effort to endorse PROP 8 in California via its network of church, media, and community outlets enshrining discrimination under the law for thousands of Californians and their families.
"In general, no organization, including a church, may qualify for IRC section 501(c)(3) status if a substantial part of its activities is attempting to influence legislation (commonly known as lobbying)."
See: http://www.irs.gov/pub/irs-pdf/p1828.pdf