discrimination & political/personal reasons.
IMO, it's much more a political difference, and the perception the Church overdoes pushing it's political viewpoint. And I think that's parroted and repeated as common knowledge and fact by people who have no personal experience w this "side" of BYU or LDS people. Some won't see a difference between religious belief discrimination and aggressive church politics(or what they see it as) but there is a diff in my experience.
Chalking it up solely to religious bigotry is easy to do, but it infers nothing can or will change people's minds, and I think progress can absolutely be made re this issue and public perception.