I happened to read some of the liner notes and was very impressed by Sufjan's insight and intent behind the project. Part of it reads as follows:
What did the angels renounce in the wake of the shepherds' trepidation? "Have no fear," they petitioned with trumpet blasts and a garnish display of constellations. But that's like waving a gun in a bank lobby and demanding: "Everybody stay calm!" Music, of course, works much differently. The most discriminating of chord progressions can disarm the most arrogant of men, including myself. Christmas music does this to the highest degree. It intersects a supernatural phenomenon (the incarnation of God) with the sentimental mush of our mortal lives (presents, toys, Christmas tree ornaments, snow globes, cranberry sauce), leaving in its pathological wake a particular state of mind one can only describe as "that warm, fuzzy feeling." Was this what I was after? The search for existential significance in all that sentimental oatmeal? Perhaps, but I'm not so certain that "Silent Night" and "Jingle Bells" can be used as an exegesis for the big questions in life.
Or can they? I decided to find out, continuing the tradition year after year, plummeting into the abysmal canon of Yuletide carols, strumming the banjo, shaking the bells, tipping my Santa hat to Saint Nick, all the while assembling a ramshackle mix tape of Christmas "hits" (sometimes adding my own originals), wondering "What does it really mean to deck the halls with boughs of holly?" ...At the very least, I discovered that sleigh bells are, in fact, difficult to play well (there is a technique to these kinds of things), and that Christmas music poses a cosmological conundrum in requiring us to sing so sweetly and sentimentally about something so terrifying and tragic.