One, they didn't use the term "separation of church and state", they wrote an amendment that said that the government could not control any religion and make it the state religion. The first amendment does not give us freedom from religion but freedom of religion, and two, YES, the founding fathers were all Christians, as were the vast majority of Europeans at the time.
You are right about the term ... It is easily distorted for what it means. Separation to me is not expulsion from, it means the state and it’s government is separate from religion.
I am not sure about the “all Christian” part. They did found the legal system on Judeo-Christian values though.
Liberals love to change the words without changing their deeds. Take for instance, liberal ...
I humbly suggest that you are not familiar enough with our founders if you think that they did not use the term.
“The civil Government, though bereft of everything like an associated hierarchy, possesses the requisite stability, and performs its functions with complete success, whilst the number, the industry, and the morality of the priesthood, and the devotion of the people, have been manifestly increased by the total separation of the church from the State “ James Madison
“Strongly guarded as is the separation between religion and & Gov’t in the Constitution of the United States the danger of encroachment by Ecclesiastical Bodies, may be illustrated by precedents already furnished in their short history” James Madison
“Every new and successful example, therefore, of a perfect separation between the ecclesiastical and civil matters, is of importance; and I have no doubt that every new example will succeed, as every past one has done, in showing that religion and Government will both exist in greater purity the less they are mixed together” James Madison
“Believing with you that religion is a matter which lies solely between man & his god, that he owes account to none other for his faith or his worship, that the legitimate powers of government reach actions only, and not opinions, I contemplate with sovereign reverence that act of the whole American people which declared that their legislature should make no law respecting an establishment of religion, or prohibiting the free exercise thereof, thus building a wall of separation between church and state.” Thomas Jefferson