Why are all the clergy who preach social reform expelled from their churches?

I omit any reference to other churches. Catholic Priests may and do preach social reform. But they must preach social reform on Christian lines. No Catholic Priest may preach social reform in the socialistic sense of the word, according to the anti-Christian principles of, say, a Karl Marx. Any Priest who would do so, and persist in doing so, would be expelled from the Catholic Church. Socialism, in the ordinary sense of that word, is theoretically self-contradictory; psychologically opposed to the very nature of human beings; practically impossible from the viewpoint of production and distribution; religiously evil, and ultimately ruinous to social and individual liberty. A socialistic system is never likely to become universal, and sectional experiments in socialism have always failed.

Radio Replies Volume 1 by Rev. Dr. Leslie Rumble MSC and Rev. Charles Mortimer Carty