In the first place, was Christ ever a part of what we think of as the Christmas celebration? Most of our traditions came to us by way of pre-Christian, pagan European tribes. The date we celebrate is because of the pagan mid-winter celebrations of the birth of the sun.
But those are other issues addressed in other places. My thought is that since Jesus came to Earth to be a sacrifice for our sins, we should always remember His death and resurrection while celebrating His birth. The letter “X” has often been used to signify the cross, so using it now does not take Christ out of the picture, but helps to put His birth in focus of the reason He came: the crucifixion, which saved us from the power of sin in our lives. So, to one and all I say: