I've noticed: it's not unusual for people to become offended and to rapidly lose all respect for a critic if this critic dares to cross the fence that's been raised between religion and academics in almost every sphere outside UD (and why should a fence be there at all when both have the aim of pursuing truth?). A reading of a poem or novel that finds a significance that resonates to any degree with Christianity is automatically assumed (not even so much by academia as by amateurs who have a blatantly liberal education and an unfortunately close-minded reaction when exposed to anything smacking of tradition) to be that of an ignorant pietist, determined to find validation for his or her faith in the works of every writer of note.
So avoid speaking of imagery of redemption, redemptive suffering, fulfillment in the transcendental. Such subjects are too close to the danger zone. Anthropologists and scholars of religious phenomena would likely have no objection to a person finding such references in the smallest minutiae of cultural production (though these scholars tend to have a rather different explanation for the existence of such ideas than I might, tending in the tradition of their discipline to put the cart before the horse and assuming that the ideas exist because of the ritual, not the rituals because the ideas are true). But to the reactionary, the findings are offensive and untrue because all-too familiar.
Why indeed should we "make everything Christian"? Why be so close-minded as to claim all good art as progeny of our own religion? I answer: we don't have to contort every text to fit within the narrow lens of an archaic and domineering religion. The lens isn't at all narrow! A true work of art, I think everyone will admit without too many qualifications will address some aspect of truth. And certainly it is qualified to address and wrestle with the most fundamental desires of man. However original one may wish to be in defining these fundamental desires, the fact remains that many artists see among them the desires to be forgiven, absolved of guilt, and to find meaning in something outside oneself. Yet when one finds these in art, many are offended because recognizing this desire recognizes an implicit desire for Christianity. For the fulfillment of these desires - in a totally unexpected way - is precisely what Christianity offers.