[FlamesAddiction]

The problem isn't believing in god, an afterlife, being rewarded for good deeds, punished for bad deeds, etc... The core root of what religion and spirituality is, is not inherently bad. It's the structure of organized religion that messes everything up.

The rules organized religions have that govern the way people live were developed by ancient and medieval cultures and just don't reconcile well with modern sensibilities. Some of the rules actually made sense at the time, and others were used as a way to manage the society as a whole, like promoting fertility in an era where there was high infant mortality, rampant disease, low life expectancy, and things like that. Other rules were implemented to promote production of resources that would help the people in various ways. Religion in those days was also a way of promoting economic policies at a time when the state did not look after the needs of the people. Many, if not most of them do not make sense today though, and the institutions have trouble adapting because they actually believe the rules were divine instructions because that is how they were posed by the rulers of the time

Of course many wars have been fought when people use religion as the distinguishing feature that separates populations, but I don't think there would have been fewer wars or less violence without religion. People would have just found other justifications to expand, take resources, spread ideology, and so on. It's what our species does. As the world moves into a more post-religion state, I don't expect few wars. The ideologies will change, but they will still clash.