Abbreviating the word Christmas to Xmas does not 'cut Jesus short' as your Emailed question suggested. Before we explain this, let us first discover where the "X" in Xmas came from and then provide a little history
The word for Christ in the Greek is Christos (which is Strong's Concordance #5547). In Greek, the twenty-second letter of their alphabet is written as "X" (the "X" of Xmas) and is pronounced CHI. It is the first Greek letter in the word for Christ.
Saving Space
Many years ago, retailers realized they could save both space and costs by shortening the word Christmas to Xmas using the letter X to replace the letters "Christ." After a few years of this practice, however, the religious community countered with the slogan that called for Christ's name to be put back into the holiday. Their efforts succeeded primarily because, over time, advertising layouts no longer depended on the number of letters in a word.
Changing the Christmas holiday's name to Xmas does not disrespect the Lord. This is because most people (whether they go to church or not) realize Christ never really was in the holiday in the first place. Most know that its origin is based on pagan, not Christian, beliefs and practices.
These facts about Xmas should be no surprise to most people, since every year we are reminded by the media and even ministers that Jesus was not born near December 25.
In fact, a good argument can be made that he was born in the fall of the year, around our September - October period, in 5 B.C. The date of December 25 was picked by the Catholic Church many years ago because it was when the pagans had an important festival.
Marketing Strategy
The Catholics believed that if the church adopted some pagan holidays and stripped off some of the more blatant non-Christian activities ("Christianizing" it in a sense) it would be in a better position to attract the pagans and have them convert. One such non-Christian celebration that worshipped the Sun was adopted, changed, and had its focus changed to worshipping the Son. Its celebration was eventually called the mass of Christ or Christmas.
The church, over the years, adopted and changed many pagan ideas and used them to honor Christ at Xmas. For example, the pretty balls (orbs) you might use to decorate your tree originated with the pagans as a representation of the female egg. Candles that are sometimes used around Christmas were at one time used by pagans (non-Christians) as a symbol for an erect penis (the pagans loved to worship their ability to procreate).
The wreath many people today still hang on their door around Xmas was first used, again, by those worshipping a false god, to symbolize the opening of a female's vagina.
In addition, although not used much today, years ago wreaths use to have a candle standing upright within them. It does not much of an imagination to see what they together symbolize. Even something like mistletoe, used today to solicit a kiss, had it start with the Druids.
What God Thinks
God has clearly stated what he thinks about mixing how he wants to be worshipped with the practices and symbols used by those who worship false or pagan gods. He clearly does not accept the majority of customs surrounding Xmas.
". . . take heed to yourself that you are not ensnared to follow them . . . and that you do not inquire after THEIR gods, saying, 'How did these nations serve THEIR (false) gods? I also will do likewise.' You shall not worship the Lord your God in that way" (Deuteronomy 12:30 - 32).
Why do churches today continue to combine pagan practices with the day, Xmas, they use to remember Christ's birth? It is simply because of tradition. Jesus, however, told the religious leaders of his day that following man's traditions in regard to God is not acceptable (Mark 7:9).
Since God does not endorse his Son's birth being celebrated, let alone with pagan symbols, shortening Christmas to Xmas does not disrespect our Savior.