Because it is universal, it exists in all life, not just in human life. Spirituality is a term used to define the relationship between life and spirit. That relationship is defined as the beliefs we have and the way we live our lives as a result of those beliefs .
Religion is organized spirituality.
Instead religion has been used, by the powerful, to divide us, to create hatred and fear, to engage in warfare. In fact, I strongly suspect that the Higher Power is shocked by nearly every aspect of the way humanity conducts itself on this planet, in creation. Though there is plenty, we have mass starvation, a planet being destroyed, non-human life being driven to extinction at a rate of maybe a couple of hundred species a day. And so millions, maybe billions of people are in search of new spirituality - meaningful spirituality. Traditional answers are that it feels right, gives us peace in a troubled world, assures us that there is something beyond death and the grave.