Why it surprises people that we, as a nation, have experienced more disunity as we become less Christianized is a mystery to me. That we, as a people, prayed to the same God was a unifying force. Those days are gone, and they are not likely to come back, short of a miracle of God, Himself. But let's not kid ourselves; the secularism today that is a secularism steeped in open hostility to the idea of a God that is, indeed, an Authority Figure, has not always been the dominant moral force in our society. I'm old enough to remember when it wasn't.
Hang on, Americans 50-60 years ago "prayed to the same God" while they worshipped in segregated churches being firebombed by the KKK and had their Reverends assassinated by gunmen. Like, is America less united today than it was in the more Christian 60s when there were frequent race riots and domestic terrorist groups running around? Idk, a graph like this
doesn't exactly say to me that everyone worshipping the same God is how you bring about American national reconcillation.