Well then I guess you've been living in a bubble most of your life, because most people, not just Christians, celebrate Christmas on December 25th.

And these self deceived Christians glory in the fact that Jesus Christ is dead and gone...with glee!!!

MERRY: mer·ry Pronunciation Key (mr)
adj. mer·ri·er, mer·ri·est

Full of high-spirited gaiety; jolly.

Marked by or offering fun and gaiety; festive: a merry evening.

Archaic. Delightful; entertaining.

Brisk: a merry pace.

The word "Merry" is defined to mean great happiness and joy. What of the word Christ?

CHRIST: Christ Pronunciation Key (krst) n.

The Messiah, as foretold by the prophets of the Hebrew Scriptures. Often used with the.

Christianity. Jesus.

Of course we already understand Christ is the title our Lord Jesus has been ordained before the foundation of the world for all of us. Now all we need to do is define the word "Mass" in Christ-Mass. This is in fact a Roman Catholic word, so let us go to the Roman Catholic Encyclopedia to find its meaning.

MASS: "In the Christian law, the supreme sacrifice is that of the Mass. ...The supreme act of worship consists essentially in an offering of a worthy victim to God, the offering made by a proper person, as a priest, the DESTRUCTION OF THE VICTIM."

Source = Page 537 of the Catholic Encyclopedia

So, in essence the word Mass is defined as death sacrifice or "Destruction of the victim" according to the Roman Catholic church itself. So, when you say "Merry Christmas" you are actually declaring with great happiness and joy that Jesus is dead and gone. Kind of like the crucifix in the Catholic church declaring He is dead and they have proof they killed Him when they display His dead body for eons before the people. The Roman priests refuse to believe Christ IS risen and Christ WILL come again. If they did they would at least remove Him from that cross!

By the way, when Santa Clause says "Ho ho ho, Merry Christmas" he is openly and boldly mocking the sacrifice of Christ WITH LAUGHTER!!
A true Christian would want to examine and guard everything they say, because Jesus our Lord said to us in Matthew 12:36-37, "But I say unto you, that every idle word that men shall speak, they shall give account thereof in the day of judgement. For by thy words thou shalt be justified, and by thy words thou shalt be condemned."