Gay marriage advocates and changing polls

Gallup reports that support for gay marriage has dropped to 40% from a high of 47% two years ago. (57% are currently opposed.) Why the drop? I suppose that it mostly has to due with the behavior of those supporting gay marriage, such as the demonizing of Mormons following the passage of California's proposition 8 or the outbursts (as illustrated by Steve Benson) of Perez Hilton after Miss California adopted the majority position on gay marriage and the same position that Pres. Obama holds:

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Politicizing the Miss USA contest
The bullying of Carrie Prejean