Because the Constitution is a positive law (man-made) contract between artificial entities know as the states and the federal united states.Artificial creations, because of their artificiality, have no 'beliefs' and no 'free will'.
All the Constitution does for the People is to enumerate a few specific positive law rights, such as the right to keep and bear arms.
No one can understand the Founders intended meaning of 'Republic', or the principals of the Constitution unless they understand certain parts of the Bible, or as the Founders referred to it....'the laws of Nature and Nature's God.'
If men through fear, fraud or mistake, should in terms renounce and give up any essential natural right, the eternal law of reason and the great end of society, would absolutely vacate such renunciation; the right to freedom being the gift of God Almighty, it is not in the power of Man to alienate this gift, and voluntarily become a slave.
John Adams, Rights of the Colonists, 1772
That these are our grievances which we have thus laid before his majesty, with that freedom of language and sentiment which becomes a free people claiming their rights as derived from the laws of nature, and not as the gift of their chief magistrate.
Thomas Jefferson, Rights of British America, 1774
[T]he laws of nature . . . of course presupposes the existence of a God, the moral ruler of the universe, and a rule of right and wrong, of just and unjust, binding upon man, preceding all institutions of human society and government.
John Quincy Adams
The law of nature, which, being coeval with mankind and dictated by God Himself, is, of course, superior in obligation to any other. It is binding over all the globe, in all countries, and at all times. No human laws are of any validity, if contrary to this.
Alexander Hamilton, Signer of the Constitution