For one thing, a written text about human experiences even today is going to be filled with violence. That is the human natural thing to do in reporting the violence that is going on around them. I am not sure why people do not judge themselves on their own human nature as opposed to their writings, accept for the fact that writings remove the issue away from the fact that humans are humans despite what they write down. We can then judge the writings and not necessarily our own human nature.
Extremism is just another method of removing one's nature a step away from their own reality so that they do not have to deal with their own humanness. Of course we do not want extremism to exist, but in reality they are the one's who are actually taking life to the fullest possible point. Most people limit themselves to the mundane.
Religion is supposed to be a way to transcend the "us vs them" tribalism that we have evolved with and is the cause of so many wars and so much violence. It's supposed to be about overcoming our animal nature. Sadly, religious differences are just another cause of tribalism, instead of a solution.
I am very glad that most people limit themselves to the mundane. They are much more reasonable to deal with. I would love for people to take their morality into their own hands as well. Of course, this type of attitude takes education, and is held back by religious indoctrination.
I also wish there were more secular community centers that dealt with moral problems or philosophy, so that non-religious folks could participate in the community-building beneficial side of religion as much as religious folk.