Are you saying Quinn is fringe or Quinn's argument on gays is fringe? I'm not sure Quinn himself is fringe. Ed Decker on the other hand... I'd say if consensus around the definition of a fringe critic could be built and fringe critics could be identified, a better place for their criticisms would be the Anti-Mormonism article. That would be consistent with WP:FRINGE because it would place the criticisms in context. That being said, I do agree with your identification of Quinn as an openly gay critic, given the nature of his criticism.