They did not think that the mysteries of divine grace, predestination, disputes over faith and works, dissertations about the real or the symbolic presence of the Saviour in the Eucharist, and all the rest were really necessary for good living and good citizenship.
They are not necessary for good living OR good citizenship.
They help, but are not necessary
Either education has not really spread very widely
IMO, in America, there were two, maybe three, generations that actually widely educated.
Before that it was either too expensive or wasn't considered necessary.
After that it is indoctronation.
Therefore a conservative cannot be a democrat. But he can be a republican. He cannot be a Christian except in the way that the Founding Fathers were Christian – able to sort out the truth from the falsehood in thousands of years of G-dtalk.
This is where I disagree with the author completely.
A conservative CAN be a christian, in every sense of the word as we know it today.
What he cannot be is a religious fanatic.