I think all religions are a partial fit to this one. I don't think most of the people of cc are part of a religion, we are part of seeking the truth of our Creator, of the spiritual part of the world we live in.
Because sin is so much of part of this world, a basic knowledge of our world has to include what our creator did for us who also live in the spiritual part, a knowledge of Christ and what He did for us.
More and more people are living only in the secular world, these people are just gathering together. They are just people who the bible calls dead getting together. There are many groups of the dead like Muslims, the Mormons who follow Jesus only as a great man, or Buddhist.