I agree with your proposition that christianity has the essential elements of a philosophy, and I would also add mythology (as Joseph Campbell illustrated in his NYT best-seller: "The Hero With A Thousand Faces" (1949) that became the PBS Special: "The Power of Myth" (1988).

Reading your excellent article I was reminded that my Philosophy 101 professor felt similarly when he assigned the class to read writings by leading figures in the most prominent world philosophies, the first of which was:

(1) christianity, rather than reading the bible, we read: "Why I am not a christian" by British philosopher Bertrand Russell;

(2)Marxism (we read Chairman Mao's "Little Red Book";

(3) Existentialism (read: John Paul Sartre's "Being and Nothingness";

(4) Platonism: "Plato's Republic";

(5) Transcendentalism: "Civil Disobedience" by Henry David Thoreau (Thoreau's fellow Transendentalist was the well-known Ralph Waldo Emerson)