I am by no means an anti-theist. I spent too many years and have too many friends who are theists to be hostile to belief in and of itself.
I've also been a student of history since the days of sixth grade indoor recess when I was the kid in the back of the room reading the Encyclopedia Americana.
Believe what you will about the virtues of Christianity in the 21st century or even its contributions to the character of the nation up unto this point, but there are certain historical touchstones you can not re-appropriate for your own purposes.
The founding fathers had uses for religion as politicians but not so much for crafting the architecture of our life together.