Or it could be the fact that the First Amendment to the constitution calls for seperation of church and state, and they find it DEMORALIZING to the other religions for them to either have representation, or no representation of any religion at all.
When the founding fathers struggled to put together the documents upon which the colonies could come together under the protection of a federal government, they realized that there were principles that had to be observed in order to make them acceptable to all parties. All were well schooled in the mores that dated back to ancient times the observance of which enabled civilized men to live in peace and harmony with their neighbors. These mores are embodied in the ten commandments.
One would be hard pressed to find a single piece of legislation which does not have its root in the Ten Commandments.
Many of them having experienced religious persecution of one kind or another, all understood that the free society they were creating had to provide a guarantee that the government did not mandate worship in any particular form, or for that matter, worship, at all.
On the other hand, as is clearly evident in many of the early documents, the existence of a Supreme Being was recognized and this existence was recognized by the newly formed government in many ways. Slogans printed on currency, emblazoned on government buildings, included in oaths of office, all attest to this fact. Governmental bodies open their sessions with a prayer to the Almighty which is offered by a chaplain whose salary they pay. Chaplains are provided at government expense to all branches of the military.
For more than two hundred years, none of these practices has ever been deemed by the courts to be unconstitutional.
To this date, the government has never even suggested, much less insisted, that any person follow any particular religious practice, or subscribe to any religion at all. In the matter of religion, all are free to do as they wish.
In recent years, there has been a spate of protests aimed, as it were, at twisting the concept of 'freedom of religion' to read 'freedom from religion'. Had this been the will of the founding fathers, then they would have made that crystal clear in their documents and there would have never been any references, at all, to a Supreme Being. However, they still would have been unable to legislate in ignorance of the Ten Commandments.
I know of no religion which does not observe, if not in every specific detail, at least the major principles embodied in the Ten Commandments. Even athiests, in general, subscribe to the fourth through the tenth commandments.
Of course, there are persons who believe that their behavior should not be constrained in any way, shape, or form. These are persons who uphold the principles of absolute and unrestricted liberty especially of thought and action with no governmental intrusion in their lives. They constantly and consistently seek to nibble away at such laws, institutions, customs, and traditions they percieve to be most vulnerable to attack by erosion. They are relatively few in number, but overpoweringly vocal in their demands. After succeeding in finding judges who can be recruited to their cause, they have frightened many politicians into revealing cowardice to defend their positions in the face of nothing more than empty noise.
There is no wall; none was ever intended; none has ever existed, except in the heads of the few who imagine it and, a la Don Quixote, joust with, as the old song title may be bent to suggest, 'The Windmills of Their Minds'.
The belief is strong that their goal is the transformation of the US to a Godless society which mirrors that of the lately disintegrated USSR.
