Founding fathers were a mixture. A number of them were Deists, which are not Christians. They believed that God created the Universe and then “left” – the absentee father God.
And it was up to us, using Reason (reason was the big thing then), to create just laws and an equitable society.
Christianity certainly played a part; I learned in school as well – but one of the things that made America unique was always that it is a SECULAR nation – perhaps the first secular nation in the history of the world.
Writing that fact out of American history rewrites all of American History.