Lee seems to feel that the Christian faith of L’Engle is not a big deal, and that it’s something that should be moved on from.... A story by a Christian author who made deliberate choices to incorporate Christian themes in a story about good vs. evil is a story with Christianity as a central theme, not just some minor element to be shrugged off.The culture as a whole is trying hard to shrug off Christianity, so it's not surprising that they wish to do so here. Nor is this the first time this has happened. Though C. S. Lewis (mentioned in the piece) and L'Engle were explicitly attempting to tell Christian fairy tales that would reinforce the faith, other authors for whom Christianity was central have also seen it stripped of its place in their works.
The Christianity of “A Wrinkle in Time” is not implied or subtle, but rather masterfully and beautifully interwoven throughout the whole story. It’s a shame if the motivations and understandings of the characters are stripped from them. At the climax of the book, when the main character, Meg, is discouraged and needs hope, it is the Bible that is quoted to her: “The foolishness of God is wiser than men; and the weakness of God is stronger than men.”
To take just one example, consider the centrality of Christianity to Malory's Le Morte d'Arthur. Malory's sources are clear about Arthur's status as a Christian king. The whole book is built around the Christian liturgical year, so much so that you won't realize that scenes take place in winter or spring except by the feasts cited. The Quest for the Holy Grail makes up the dramatic center of the work, beginning at the high water mark of the secular Arthurian kingdom and hastening its downfall as so many knights -- successful at establishing worldly goods and attaining worldly virtue -- are destroyed by the pursuit of spiritual perfections of which they fall far short. Though the destruction of Arthur's kingdom is eventuated by Lancelot and Guinevere's sin, and Gawain's sin of pride and wrath in pursuing vengeance against them, the pursuit of the Holy Grail weakened the kingdom as a practical power; it stored up treasures in heaven for the martyrs, but at substantial earthly cost.
Yet go and find any version of the Arthurian story told since the 1970s, and you'll find that some sort of paganism is presented as the real moral core of the work. Arthur is secretly a worshiper of Mithras, or really the hero(ine)s were pagan goddess worshipers, or Merlin was secretly a pagan and guided Arthur around a benighted Christianity, or....
Indeed, the one easy counterexample is Tolkien. Tolkien's great work differs in that it barely makes reference to the Christianity it nevertheless assumes as basic to its structure. This seems to have been a conscious decision on Tolkien's part. You can engage with Frodo and Sam's quiet faith based on the stars being beyond Sauron's reach; you don't need to believe in a transcendent God. You can examine the heroism of Gimli and Legolas, or their friendship across differences of species and culture and history. Aragorn's acceptance of his need to strive heroically against the winds of fate is noble in a way that a Roman or a Viking would appreciate. Only occasionally, in the whispers of Gandalf, do you get the idea that there is a hidden power directing the world, a "Secret Fire" before whose worn and tired servants even Balrogs cannot prevail.
Even at the end of the book, you have only received a hint that Gandalf is one of those beings like the 'Wrinkle in Time' messengers. If you don't read further into the legendarium, you'll never be told that Gandalf is not just a 'wizard,' but a Maiar, a kind of lower angel. Tolkien hid it for them, for reasons of his own.
