Those and other modern disciplines are organized on secular lines because competing Christian sects and ancillary faiths prevent agreement on a theological framework. Indeed, assuming that only material causes exist or need be considered simplifies the organization of modern life. Yet people rebel at the sterility of life purged of its spiritual dimension, and so Christianity and other faiths persist. Literature of course often addresses this point.
Which is why theology should be mandatory field of study. Part of basic universal academic curriculum. Theological illiteracy even among so-called Christians is another great travesty of our time. Even the current events of today have theological foundations. Conflicts rooted in theological differences...
People should know why a Calvinist and a Catholic may have conflicting views on art for example. (To be fair this does get touched on in secular Art History courses.) Or why Eastern Orthodox political culture developed differently from Western Christian world etc...Or how Muslims view the concept of a Judgment Day as opposed to Jews etc...
Back in the day, *basic* scholarship required the study of Greek, Latin, sometimes Hebrew -- and literacy in the great classics...
Oxford, Cambridge, and the American Ivy League (sans Cornell) were founded under Christian auspices...varying denominations to be sure, but still.