All that was left was the "social" Christianity. Which is nice but about as strong as cobwebs when the time comes when you need it.
Christianity was the state religion and the government had it's fingers all over it. That meant that the seminaries were run by the government indirectly and the pastorships and leadership positions in the church were handed out on the basis of who you were related to.
The Church was not a calling but a profession.
Most of the pastors and priests did not believe the tenets of their own faith. And they held those of the laity who did in contempt.
Yes, the term "Christianity" is based upon the title "Christian," and Scripture is the only sure definitive source of that term, and defines what it basically means. And which disallows most of what is called Christian.
Yet one can feel such a love for the good things of their country and culture that they feel it is the right thing to fight for it even though their country or part thereof is the evil side. Thus you did have Christians fighting each other in the Civil war.
However, note that the author here is a Catholic, and it is tell that their church can broadly refer to "Christian" while at the same time stating that Protestant churches are not worthy of the proper title "church."