Behold, I have set before you today life and good, and death and evil. Choose life, so that you and your offspring will live (Deut 30:15,19)
Those verses basically summarize what I consider religion to be all about. Most of the world's religions are trying to provide a moral code for people to live by, a deeper explanation than "be good." But really, that's the heart of the matter.
I finally figured out why I like Judaism better than Christianity. It's more resistant to fundamentalism (though not immune).
Fundamentalism is a disease which attacks religions. Monotheistic religions are particularly susceptible to it, but polytheistic and atheistic religions are not entirely immune. The core idea of fundamentalism is that questions are forbidden. A "good" fundamentalist does whatever they are told without thinking or asking why. They learn the arguments to defend their beliefs. They may even be encouraged to come up with more arguments. But they are never allowed to question the leaders of the fundamentalist movement.
Fundamentalism is a tool used by small groups of people who want to control large groups of people. The leaders declare things to be the divine word of God, which obviously means it is right and there is no point in discussing the matter further. By threatening various untestable punishments (you will go to hell when you die) and promising untestable rewards (you will get 70 virgins when you die), the leaders can scare people into following them. They use whatever is convenient to support their position. Many fundamentalist positions are directly contradicted by other parts of the holy texts they cite, but those parts are just ignored. It is all about power, which is never a good place for religions to go.
Fundamentalism is the best argument for separation of church and state. The danger is not as much in the state being controlled by the church as it is in giving political power to people that are leading religions. The natural result will be that people who are the most willing to do anything to get power will end up leading the religion. These are almost never the people you actually want running your religion. Their concept of good and evil is normally something that would quickly lead to chaos if everyone followed it.
Christianity was overtaken by fundamentalism very early in it's history. Once the Roman Emperors realized that the church could be used to control people, Christianity had basically no chance. The decay of the church led to some really awful popes during the middle ages. The protestant reformation was to some degree a rejection of fundamentalism.
The cure for fundamentalism is the Enlightenment and the ideas that spread during that time. Science and religion are not enemies (they don't address the same topics, so they can't really disagree), but science and fundamentalism are. The enlightenment was to some degree the result of the protestant reformation fighting down fundamentalism.
Christianity's early infection of fundamentalism distorted the religion quite badly. The fundamentalists got to control what made it into the bible and what didn't. Since they had power almost from the beginning, there aren't many older editions of the bible that have different descriptions of things. The fundamentalists made a great effort to destroy any "holy texts" that disagreed with their desired religion. And they set the agenda for the early discussions of how to practice the religion. The result is that very few churches encourage actual discussions about what Christianity is or how to be a good Christian. It is almost always something where you are supposed to listen to the priest and do what they say. Christian worship services resemble lectures, with one person standing up and telling everyone what is going on.
Judaism has had fundamentalism to various degrees over time, but in general there has always been the idea that you should learn everything well enough to discuss it. And when people discuss things, they will tend to disagree. There are disagreements throughout Judaism as to what the commandments mean and how strictly they have to be followed. Judaism encourages questioning. The worship services generally have discussions about what the readings mean and good Jews are supposed to question the commands and determine what they mean.
There is one major area where Judaism does have fundamentalism: Israel. Many Jews get upset at discussions about whether people should support Israel's actions. They consider people who even ask questions and try to discuss the subject to be anti-semitic. As far as I can tell, it is impossible to have a rational discussion about Israel with most groups of Jews. The mere suggestion that Israel might be doing something wrong almost immediately gets many people upset to the point of yelling.
This has been becoming more clear to me over time. At the Rosh Hashana dinner, people at the table I was at were talking about Israel for a while in a way that basically implied everyone there obviously supported everything Israel did this summer. A bit later, someone said something about immigration, but then quickly decided that it might be too controversial to talk about at a holiday dinner. It seems perverse to me that a group of people would think that talking about killing people is not controversial, but talking about treating people with respect is.
It is important to note that supporting Israel is not a fundamentalist position. The fundamentalist position is supporting Israel regardless of what happens and attacking people who want to have a real discussion about Israel. There is nothing fundamentalist about attacking people who think Israel should not exist. The relevant hypothetical question is what would Israel have to do for you to stop supporting them?
Most of the time, Israel is not relevant, so this little bit of fundamentalism can be ignored. This leaves the rest of the religion and discussions about good and evil. But maybe I should just switch to UU, which might actually be immune to fundamentalism (though it might go all the way to the other side, where anything is considered acceptable and there is no basis for agreeing on morality).
In the late 19th century, a new wave of fundamentalism began to grow that is now overtaking the major world religions. It is concentrated in Zionism (for Judaism), Revelationism (in Christianity), and whatever movement the Islamic terrorists are following. There is a cultural battle going on throughout the world between the fundamentalists and the enlightenment. Most of the fundamentalist groups are trying to kill anyone that disagrees with them. They seem to be ignoring that this will probably lead to a nuclear world-war if they aren't stopped. The fundamentalists are working together (while hating each other) to destroy the world. They are serving the purposes of death and evil very well. I'm not sure what can be done to stop them.