I can understand your doubt, but here's the thing. All those various statements like "I'm not a fence sitter" and so on? Those are direct quotes from a massive number of church sermony type speeches I've heard over the years. She's either done her homework on "crazy bible thumper" or actually knows all this stuff and intentionally went overboard just for money, which would go against her own beliefs anyway.
For my part, she seems to actually believe all that stuff (well she acts like it, quotes a large number of bible sermon things, and generally doesn't indicate having an original thought in her head), but I'm pretty sure the presence of the camera did play a part in how totally insane she got for that last part. I think she wanted to "send a message" to America on how good a christian she is, like "I'm being watched by everyone in America, I better not make a fool of myself", and yes I'm fully aware of how funny a supposed thought that would be, but just talk with some people in the bible belt and you see it's actually pretty common. These people LIKE drama, an epic event, they need it. She WANTED to be in a huge struggle against evil, to be the lone person standing for what's right when everyone around her is against her.
Or she faked it all, but she had to have done some homework and taken some acting classes to get it down pat. I'm leaning towards what seems more likely...