The other members of the group didn't kick out that gay singer out because he's gay—that would violate university rules—but because of what that gay singer believes about being gay:
The Christian a cappella group Psalm 100 voted unanimously Sunday night to remove one of its members, senior Will Thomason, because of his views on homosexuality, members said.... Psalm 100’s constitution mandates that members of the group act in accordance with ideology laid out in the Bible, said Blake Templeton, general director of the group. Templeton stressed that Thomason was not removed because of his sexual orientation.
“It’s really easy in this situation for the focus to be on this one thing—the homosexuality,” he said. “It wasn’t about that. It was really about a disagreement with something that was clearly written in Scripture and in the Bible and we just have to base all of our decisions, constitutionally... on the Bible.”
The group is coed, performs in churches, and I believe the bible has something to say about women keeping their mouths shut in church.
Here's Psalm 100's Facebook page—where folks are expressing sympathy for the members of Psalm 100 who voted to kick Thomason out—and I'm thinking Blogtownies, particularly the non-NALTs who read Blogtown, might want to jump in. Psalm 100's Twitter feed is here, their website is here.