Many Christian parents who are just beginning to homeschool start out seeking a curriculum that not only meets their learning needs but one that also fits in with their Christian beliefs. As time goes by many of those parents find that their homeschool curriculum is really good at one... or the other... but not both.
As Kerry from North Carolina says in her article about Homeschooling as a Christian "We are Christians, but aren’t really homeschooling for religious reasons..." and I suspect the difficulty finding curriculum to handle both concepts may have had a hand in making that decision. Either the religious content is first priority and the educational content suffers or vice-versa.
Religion is personal. Your education is something you will show to everyone you ever come in contact with. When it comes to homeschool curriculum and religion, I see them as completely different animals who should be contained in two separate cages for the sake of the trainers (parents) and the audience (students).