I enjoy learning the history of Christmas. I was amused to learn that St Francis of Assisi staged the first nativity. It baffles me that people are so adamant about Christmas being about the celebration of Jesus' birth. The Bible doesn't address such celebrations and doesn't mention the date. Pope Julius assigned Dec 25 centuries after the fact. 
People are free to celebrate (or not) as they wish, that's the good news. In reference to your Dickens, my favorite holiday meme: Bah! Humbug!