What a thoughtful and good observation your friend has, Joe. I do appreciate his perspective and he is right about how we should observe all of Christ in our celebration of the Lord's supper. We should also watch for the dangers of syncretism in our practices. These arguments are nothing new of course and I found the following article by JC Ryle to be quite compelling in my consideration of how I regard Christmas.

http://www.biblebb.com/files/ryle/what_think_ye_of_christ.htm

The Chestnut Mare