Well considering that when one carefully studies the various writtings of many of the founding fathers and finds that a lot of them were practicioners of deism, as well as other heritical paths such as apotheoscy like Washington and others (masons and other secret colleges) and wore the matle of the so called "faithful" in their country of origin to hide from persecution; one must also consider that the founding fathers did not wish only to avoid a state controlled religion, but to exclude the state from promoting or having any part whatsoever in religion of any kind.
In the words of ole Tommy J himself:
"No man shall be compelled to frequent or support any religious worship, place, or ministry whatsoever, nor shall be enforced, restrained, molested, or burthened in his body or goods, nor shall otherwise suffer, on account of his religious opinions or belief; but that all men shall be free to profess, and by argument to maintain, their opinions in matters of religion, and that the same shall in no wise diminish, enlarge, or affect their civil capacities."
Basically:
The First Amendment contains two clauses about the Freedom of Religion. The first part is known as the Establishment Clause, and the second as the Free Exercise Clause.
The Establishment Clause prohibits the government from passing laws that will establish an official religion or preferring one religion over another. The courts have interpreted the establishment clause to accomplish the separation of church and state.
The Free Exercise Clause prohibits the government from interfering with a person’s practice of his or her religion. However, religious actions and rituals can be limited by civil and federal laws.
Religious freedom is an absolute right, and includes the right to practice any religion of one’s choice, or no religion at all, and to do this without government control.