Remember the old phrase “Give credit where credit is due”? Celebrating Christmas without a belief in the Savior is what I would call “eating the seed corn.” There is nothing contributed to the next generation. To continue Christmas, you have believe in the real meaning of Christmas, otherwise it will become a silly secular annual event used by commercial interests and eventually die out.
I don't "rage" at Christmas in the slightest, nor do I feel in the least upset that all these beautiful traditions are, at the core, based upon an event in which I do not believe.