Secular America Government

Many believe that the United States government is built on Christian foundations. They say the the political system represents a Christian ideal form of government. Many believe that the founding fathers expressed Christian values while framing the Constitution. How true is this?
It is true that America statesmen did practiced Christianity, but most of the founding fathers broke away from religious thinking. Instead of relying on faith, they used reasons and science to guide them. There are a few Christians fundamentalist that are trying to convience the America people to return to Christianity of early America.
The founding fathers rarely practiced Christianity. They supported the free will of many religions, not just Christianity. Most of them were Free-Masons. Free-Masons says that men worship according to their own conscious, not just Christianity. The Masons welcomed anyone from any religion or non-religion, just as long as they believed in a Supreme Being, not only the Christian God.
The Constitution reflects a secular government, protecting the freedom of any belief or unbelief. It says nothing about Christianity only. George Washington stated in 1789, that every person "ought to be protected in worshipping the Deity according to the dictates of his or her own conacience." In 1799 George Washington became a Master Mason and was a Free-Mason until he died.
Thomas Jefferson denounced the superstitutions of Christianity. He did not believe in spiritual souls, angels or godly miracles. He admired the morality of Jesus, but did not believe in the Trinity or the miracles of Jesus. He believed in materialism, reason, and science. He had no religion, but his own.
John Adams flatly denise the doctrine of eternal damnation. James Madison, he had no conventional sense of Christianity. Although Benjamin Franklin received religious training, but he rebeled against his parents Christianity.
Thomas Paine said, "I do not believe in the creed professed by the Jewish church, by the Roman church, by the Greek church, by the protestant church, not by any church that I know. My own mind is my church." Personally I agree with Thomas Paine.
There is nowhere in the Constitution do you find a single word mention of Christianity, of God, of Jesus Christ, or any Supreme Being. There's only two reference to religion that occurs. You will find it in the First Amendment, which says, "Congress shall make no law respecting an establishment of religion," and in Article VI, Section 3 states, "no religious test shall ever be required as a qualification to any office or public trust under the United States."
How can people in America say that the Constitution of the United States of America is based on Christianity?
Thank You.