Rolling Stone on Obama and Prop 8

When Rolling Stone criticises Obama, you know there's rumbling on the left.

In its Prop 8 post mortem, Rolling Stone says:

"It didn't help that Barack Obama refused to support gay marriage, and voiced his opposition to Prop 8 as a narrow constitutional matter. Indeed, Obama was so weak on the issue that Schubert [Frank Schubert, the consultant who directed 'Yes on 8'] highlighted the candidate's opposition to gay marriage in a mailer targeting African-Americans, and used his voice in a statewide robo-call. "We were able to quote him directly on the core issue in direct mail and in calls at the end of the campaign," says Schubert. When African-Americans in California went to the polls on Election Day, 70 percent of them voted to ban gay marriage."

http://www.rollingstone.com/politics/story/24603325/samesex_setback/print

Obama was quoted in anti gay marriage mailers, and Obama's voice and words were used in anti gay marriage robo-calls, targeting the black community? Then why is everyone blaming the Mormons? The anger appears to be misplaced.