It is a little tiresome to have to repeat explanation year after year, but I know people on Facebook who persist in posting crackpot memes like this: “It's Christmas...not X-mas!!! Don't remove Christ from HIS birthday!!! Post this if you agree...Please don't X out the Lord!!!!!”
Here we go again. The X in Xmas is not the x in algebra for an unknown quantity. It is the Greek letter chi, which shares a shape with the Latin letter x. Chi is the first letter in Christos — Christ. Xmas is an abbreviation of Christmas, not a subtraction of Christ from Christmas.
(Merriam-Webster traces the first use of "Xmas" for "Christmas" to Anno Domini 1551.)
To see a parallel, imagine someone objecting to St. John because John was a saint, not a street.
I would like to see everyone have a pleasant holiday season, my fellow Christians among all those who have occasions to celebrate this time of year. I think that everyone would have that more pleasant holiday season if fewer people were determined on inventing reasons for offense where no offense is intended.