I am Catholic - so not sure how the Heathen's celebrate, nor do I care. We're currently in Advent in our church calendar, preparing for the arrive of Christ this month. Immaculate Conception is celebrated today, and it's a holy day of obligation for us.
Do you care about the history of the Church, and of where its holidays came from? The Catholic Church emerged from the schism of the Imperial Church in about the 5th-6th century (as did the Orthodox Church). So its traditions go back to the Imperial Church founded by Constantine for political purposes. Part of that was co-opting major Pagan holidays so converts could go on celebrating at the times and (mostly) in the fashion they were used to, making it easy to convert.
Celebration of Christmas in December dates only from the early to mid 4th century, coinciding with the founding of the Imperial Church in 325 at the Council of Nicaea (now considered the first Ecumenical Council). Earlier than that, Christians celebrated Good Friday and Easter (although it may not have been on the same date) but not Christmas.
Of course, it really doesn't matter when Jesus' actual birthday was, and there is nothing at all wrong with Christians celebrating it on Dec. 25th or any other day of the year they prefer. Cool with me. I'm just saying that when you said:
Christmas is the celebration of the birth of Christ. Christians celebrate this event. Non-Christians should report to work that day rather than use a Christian holiday as yet another excuse for a day off hitting the bottle.
You were speaking without knowledge. It's our holiday, too -- in fact, it was ours before it was yours.