You are correct. Their views were hardly a secret.
George Washington in 1790 writes:
For happily the Government of the United States gives to bigotry no sanction, to persecution no assistance, requires only that they who live under its protection should demean themselves as good citizens, in giving it on all occasions their effectual support.
John Adams in 1796 writes:
The government of the United States of America is not in any sense founded on the Christian Religion
Thomas Jefferson in 1823 writes:
And the day will come when the mystical generation of Jesus, by the supreme being as his father in the womb of a virgin, will be classed with the fable of the generation of Minerva in the brain of Jupiter.
James Madison in 1817 writes:
Is the appointment of Chaplains to the two Houses of Congress consistent with the Constitution, and with the pure principle of religious freedom?
In strictness the answer on both points must be in the negative. The Constitution of the U. S. forbids everything like an establishment of a national religion. The law appointing Chaplains establishes a religious worship for the national representatives, to be performed by Ministers of religion, elected by a majority of them; and these are to be paid out of the national taxes. Does not this involve the principle of a national establishment, applicable to a provision for a religious worship for the Constituent as well as of the representative Body, approved by the majority, and conducted by Ministers of religion paid by the entire nation.
The establishment of the chaplainship to Congs is a palpable violation of equal rights, as well as of Constitutional principles: The tenets of the chaplains elected [by the majority] shut the door of worship agst the members whose creeds & consciences forbid a participation in that of the majority. To say nothing of other sects, this is the case with that of Roman Catholics & Quakers who have always had members in one or both of the Legislative branches. Could a Catholic clergyman ever hope to be appointed a Chaplain? To say that his religious principles are obnoxious or that his sect is small, is to lift the evil at once and exhibit in its naked deformity the doctrine that religious truth is to be tested by numbers. or that the major sects have a right to govern the minor. .