The X standing for "Christ" has nothing to do with cancelling him out of the holiday. The first letters of Christ's name are written with an X in Greek (Chi). It's just a simple abbreviation in a foreign language.
Unfortunately no. You may, however, rub the fact that X is an ancient way of writing Christ in their faces and public humiliate them, if you so desire.
Who cares about pushing Christ out of Christmas. The fact of the matter is that Xmas is not the correct spelling for it. Since when people are so lazy not to write full words anymore?