If fundamental things were simple, everyone would understand.
When we say something about the world we rely on our listeners to respond in some better way than killing us, rely on them agreeing with us that there is a job to be done to find the meaning of the words we use and test their truth.
Everything we say, before it is anything else, is a plea to listen.
The more general our words, the louder is this plea. If I say make money, make a success of yourself, do that before anything else, I am asking my listeners to agree with me on what success is, what the best use of money is, to consider something different from what they then think. I am telling it to them because it is different, because it is news to them. That is dialog, that is how it should be. How it is is very much otherwise.
Consider the Jews. They claim to have made an agreement with god to follow his rules. Not an agreement with each other, only with god. The others, their fellow Jews, have an limited role to play in this agreement. In ritual repetition of the rules in each others company they help each other remember the rules. They like each other only to the extent they provide each other that service. They like each other only when and only so far as they obey the rules. If they think you do not obey god's rules, then you are useless to them in the role of memory aid, and you will be ejected from their community. Nothing in their relation to you, memories of love or friendship or sympathy will restrain them from expelling you. Read the bible if you don't believe me. If you grew up in a Jewish neighborhood like I did you know it from personal experience.
So before talking about holocausts, racism, fanaticism, and the political dangers of idealism, every Jew must deal with this problem, answer this question: Is it true or not that fundamental to Jewish behavior is the threat and practice of excluding individuals from their community on the basis of ritual repetitions rather than obedience to rules which they can justify as being good? And isn't this a recipe for fundamentalism? Or drop the extra words, isn't this fundamentalism itself?
Let us give it a definition. When you can be ejected from your people at any moment, you live in permanent insecurity. When there is no distinction between a time of safety in your life and a time of danger, the rules of living at war apply at all times. Everything is permitted to those who do not know peace and have no peace time life to protect and return to: fundamentalism as we know it in practice.