A religion is a group of people with a set of fundamental beliefs.
A religion doesn't only define people who believe in a deity or in religious texts.
Most people have some form of religious values, and we can list numerous things that everyone does that came from religious origins.
So for example people getting married & divorced, having a monogamous relationship as a norm of society, celebrating Christmas, Easter, Halloween, shaking hands with our right hand, having some form of legal system where people are punished with pain, etc, much of this came from religious values.
Virtually any time a group of people get together, and decide to follow the same set of beliefs, that later became a religious value, and from the history of humanity, we can show that whole nations have been divided by their religious belief systems.
Thus each African & American Indian tribe, etc, had different religious beliefs, and that then established their separate identities.
There is no way really to be free of religious values, as our society is governed by the principles that came from it... Even if we left society, and then created a new system of beliefs, if multiple people had that same belief, that would be a new religion.