It's a common sign this time of year. The sign that says "Xmas" instead of Christmas. Understandably, many Christians get upset when they see the sign. Not only have they removed Christ from Christmas, but they have crossed him out with an "X".
I don't believe that Christians should be offended when they see the "Xmas" abbreviation - because, in reality, "Xmas" is an abbreviation based upon the Greek language. While I do not know Greek, it is my understanding that when Christ is spelled in Greek, the first letter is "X". So, biblical scholars, Bible students, and Christians have, for centuries, used "X" as an abbreviation for Christ. "Xmas" is simply an abbreviation for Christmas, which actually recognizes the name of Christ.
While Christians should be concerned about the commercialization of Christmas and, in a practical sense, Christ is largely ignored at Christmas time, their concern about Xmas is misplaced.