Is ousted "American Idol" contestant Mandisa anti-gay? The 29-year-old soul singer and outspoken Christian, who was voted off the hit Fox show Wednesday, says she would not perform at an event held in support of the gay community. Mandisa, a native of Antioch, Tenn., tells Advocate magazine, "Based on what I believe, I'm not an advocate for (being gay), so it's nothing I would take part in." Still, she says in an interview in the magazine's Web site, she's "really upset" by speculation she endorses the ex-gay movement _ a collection of Christian groups that seek to alter sexual orientation....