Easy. As Galileo said, "The Bible tells me how to go to Heaven, not how the Heavens go". The same principal can be applied to every aspect of life, including GID. Christian faith is not complicated, but some people seem to want to make it so.
Jesus message is about abolishing the artificial barriers that prevent people from connecting, and breaking down hierarchies. If someone is using the Bible to push a particular barrow, they are probably being selective in their use of the Old Testament, or putting the Letters of St Paul, for instance, above Jesus parables and other "direct" quotes.
Either way they are building walls, not pulling them down, and have missed the point completely. I pity them for leading stunted lives.