I think your analysis of our differences is true to a great degree. Judaism is a corporate enterprise. It does not recognize the separation of religion and state. The Torah, both Written and Oral, is a legal and ethical code for both individuals and the state, addressing all aspects of personal and corporate life.
The Gospels, on the other hand, are not concerned with the details of politics or economics. Jesus is talking about a revolution of the individual. He may have thought that to change the whole we must begin with the parts (I myself agree with this), or he may have believed the endtimes were upon him and that history and the vehicles of history such as the state were coming to an end so there was no need to speak to these entities. Or he may have felt that nothing could be or needed to be added to the Hebrew prophets and their centuries-long call for social, political, and religious revolution. Whatever his reasoning, one is hard pressed to run a country or an economy or even a world religion based on the principles of the Sermon on the Mount.
This was probably a nonissue until the Conversion of the Emperor Constantine and the eventual transformation of Roman Empire into the no less oppressive Holy Roman Empire. The more power the Catholic Church accrued the less Christian it became. Martin Luther's Reformation was a return to Jesus, but this simply resulted in a plethora of Jesuses each supporting the ideology of the state or group that worshipped him. When we go back to the original texts of the New Testament and just try and understand Jesus as his original listeners may have understood him, we are engaged in a very dangerous and revolutionary act, for what we find and hear is not the Jesus of this or that denomination or political party, shaped to sanctioned to their policies, but the real Jesus demanding a revolution of the heart.
When President Bush II said Jesus was the philosopher who influenced him the most, no one asked him where Jesus actually influences his policies. Bumper stickers asking “Who Would Jesus Bomb” show just how absurd it is to use Jesus to justify the brutality of the state. To put it bluntly: in a country driven by greed and addicted to oil, and so trapped in the politics of hate, fear, and xenophobia, Jesus is a very troubling role model. So we are offered a number of faux-Jesuses instead: the Jesus of the Prosperity Gospel, for example, who wants everyone to be rich (camels and needles be damned), and the Warrior Jesus where the Prince of Peace sanctions the ways of war, and the Jesus who hates homosexuals, Jews, blacks, and Democrats.
It seems to be that much of Christianity in the United States, like Islam in places like Saudi Arabia, Pakistan, and Iran, and Judaism in Israel has been highjacked by those who use religion only to solidify their own power. This is why we need to go pack to the prophets of justice and compassion in each of these traditions and reclaim the true revelation they all share: to love God and to love our neighbor.
What I hope isn't getting lost in our conversation is just how radical the Ten Commandments and the Sermon on the Mount truly are.