What Does Religion Boil Down To?

I see religion as a belief system. It's basically just a way to see the world. We humans are pretty small and insignificant in terms of the universe, so we need a lens to judge everything by to make the disorder and chaos of the world make more sense. We don't like being small and out of control, so we use religion to make the otherwise random and meaningless make sense. This need has always existed. It is a fundamental human need to explain our surroundings and exert some kind of control over the world and our lives. I'm sure that the Palaeolithic Neaderthals had just as much need for control and order as we do, maybe even more so considering how much less scientific understanding of they world they had. Of the types of ur-religion hypothesized by Clottes and Williams in "Palaeolithic art and religion" sympathetic magic seemed to me like it falls into the category of people trying to control the world whereas shamanism is more of an attempt to explain the universe, which I feel is a more classic definition of religion. Another aspect of the shamanism that best fits the definition of religion is that people believed in spirits and supernatural dimensions/realities. This is still true if you compare it with other religions' explanations of an afterlife. Just as Shamans brought Palaeolithic people closer to alternative realities, many people today follow their religious teachings to bring them closer to their perception of God and the afterlife.
I really like the concept of how religion is such a necessary and fundamental part of human life. As an atheist I lean toward a more scientific and empirical explanation of the world, and I like being able to explain religion in a similarly technical way as opposed to the dogmatic explanation usually given by those of different belief systems. It's cool to think of religion as a psycological or biological instinct humans have had for tens of thousands of years and not just something created by scholars or industrialized society. While I understand the joy that the majority of people in the world feel from having complete faith in their religion and living by its principles as the absolute truth of the universe, I just can't help but think that the world could be more harmonious if people accepted that religion is a belief system, not the belief system. It just strikes me as close minded for anyone to put their own beliefs as truer in an absolute sense than someone else's. If you can answer the question what is religion, and recognize that other religions and belief systems exists, how can anyone say that their beliefs are right and someone else's wrong? So here's what it all boils down to: religion is a particular set of beliefs and religious truth is nothing more than a type of cultural relativism.