I never really thought of it this way, but Dennis Prager nailed it when he wrote in Human Events
If you want to predict on which side an American will line up in the Culture War wracking America, virtually all you have to do is get an answer to this question: Does the person believe in the divinity and authority of the Five Books of Moses, the first five books of the Bible, known as the Torah? .... That is why one speaks of Judeo-Christian values, but not of Judeo-Christian theology. Torah-believing Jews and Torah-believing Christians have very different theological beliefs, but they agree on almost all values issues -- largely because they share a belief in the divinity of the same text.... That a belief or lack of belief in the divinity of a book dating back over 2,500 years is at the center of the Culture War in America and between religious America and secular Europe is almost unbelievable. But it not only explains these divisions; it also explains the hatred that much of the Left has for Jewish, Protestant, Catholic and Mormon Bible-believers.And it explains why Jews, Protestants, Catholics, and Mormons can disagree on specific points of theology, yet can ban together in support of Judeo-Christian moral issues, because they stem from what God said in the Torah.For the Left, such beliefs are irrational, absurd and immoral. Which is exactly how most conservatives regard most leftist beliefs, such as: there is nothing inherently superior in a child being raised by a mother and father rather than by two fathers or two mothers; men and women are not basically different, but only socially influenced to be different; Marxism was scientific; that the Soviet Union was not an evil empire; it was immoral for Israel to bomb Saddam Hussein's nuclear reactor; morality is relative to the individual or society; there is no moral judgment to be made about a woman aborting a healthy human fetus solely because she doesn't want a baby at this time; material poverty, not moral poverty, causes violent crime, etc.