My intention is to learn more about this 100 year effort by the Catholic denomination to nationalize American health care, today is the first I have heard of this.
Why do you assume advocating for health care reform means to nationalize it?
In 1919 the Bishops came out for socialized medicine. They have advocated it ever since. During the New Deal they sold their souls to the Devil by accepting the idea that government income transfers were the equivalent of private charity. In effect they outsourced one of their prime responsibilities to government.
The Rev. John Augustine Ryan (1869–1945) became known as "Monsignor New Deal" for his outspoken advocacy of New Deal policies. He was an advisor to the Bishops. His books on the subject are enough to make a free-market advocate puke.
There are many Catholics who recognize the fallacy of turning the economy over to the government. Unfortunately, so far we're in a minority.