The liberal group People for the American Way mashed up Perry's invite with snippets of a few of the invited speakers doing their thing. Their thing tends to be anti-gay and anti-non-Christian stances, expressed so virulently it nearly looks like satire. But it's not, at all.
Clearly Perry isn't worried about drawing an explicit connection between government and religion, but an explicit connection to this particular brand of extremist religion seems certain to damage his national chances. True, Perry's not the one spouting this stuff himself (it's sort of like picking up dog droppings with a plastic bag — getting the dirty job done but keeping his own hands clean). And it's doubtful that there's much overlap between subscribers to People for the American Way's YouTube channel and the far-right evangelical voters Perry is dog-whistling at with his role in this event. If Perry is trying to present himself as the pro-business, job-creating, experienced alternative to Romney, it's not surprising that he would want to play up his Christianity, when Romney's Mormonism is part of what makes some likely GOP voters uncomfortable with him as a candidate. It's also a way to siphon off the evangelical crowd from Bachmann.
But Perry's theoretical appeal would also need to come from his electability in a general race. Gay marriage might be in the news, but it's far less a wedge issue than in recent years, especially among young people of all political affiliations. (And Oprah! She's perhaps the one thing around which Americans of all stripes can unite.) Perry wasn't blindsided with speakers he didn't know anything about; he sought out the AFA specifically as a co-sponsor. Swing voters, and even middle-of-the-road Republicans, aren't going to love his frothing-at-the-mouth friends.