They should be restricted to unalterable factors, like gender and race. We already protect religion which is a changeable behavior. Homosexual hate crimes are common and becoming more so. There have also been rapid religious changes in such diverse areas as women wearing hats in church, female ordination, concepts of hell and heaven, the nature of Satan, etc. Finally, many decades or even centuries later, conservative denominations complete the transition.
Social change tends to be very slow with in many conservative denominations.
They broke away from their abolitionist parent organization over slavery in 1844. They believed, at the time, that slavery was not a sin according to the Bible. Almost all Fundamentalist and Evangelical congregations and denominations have not yet altered their stance on homosexual rights, marriage and ordination. Some do accept homosexual members as long as they remain celibate. The Olin T. Binkley Memorial Baptist Church in Chapel Hill NC had approved the ordination of a known homosexual.