So, prove it. Provide evidence that comes from a non-mormon site.
From the Democratic Underground, surely no lover of Mormons. PRESS RELEASE: "Catholics stand with Mormons: Prop 8 protestors are 'bigots, intolerant'
From the New York Times, surely no friend of the Mormons. Mormons tipped the scales in ban on gay marriage
Here is a wiki with many sources on who helped with Proposition 8. California Proposition 8
From Minneapolis. Proposition 8 and Beyond
From the San Francisco Chronicle. Catholics, Mormons allied to pass Prop. 8
The Boise Backpage contains links to other news organizations and websites about Proposition 8. I saw the Wall Street Journal in the list. The Mormon (LDS) Church and Proposition 8 -- Contributions, Campaigning and Consequences
On a personal note, my mom is from California, her brother, my cousins and members of the LDS church in Fresno worked tirelessly to get Proposition 8 passed. I have several cousins who want nothing to do with church and they were out there working as well to pass Prop 8.
I do know for a fact that they worked in coordination with other organizations and religions to go door to door and tell people about Proposition 8. They also went to or ran call centers to contact people.
I need to get my mom from the airport, I am sure I will have many replies when I check back in tomorrow.