And the Protestants went through the "social gospel" thing in the 19th century -- not so bizzarely, because such was not available at the time. It always struck me that the "social gospel" was propounded by those who had apparently had little contact with the actual gospel.
I went to a Catholic college in the late 60s. Senior year we had a required course in sacramental theology; naturally, we read such monuments of Catholic scholarship as Teilhard's Phenomenon of Man (hey, at least he was nominally Catholic), Robinson's Honest to God (of which C.S. Lewis remarked, "I'd rather be honest."), Harvey Cox's The Secular City, something of Tillich's that I forget, . . . and so on. I was young and I assumed that in a Catholic college I could trust what was taught. (I found it all incredibly boring, though, and only managed a C.)