Pastor John MacArthur says:
"Many people today miss Christmas because they don't realize they are sinners. Thus they ignore Christ. They don't show any interest in the Savior because they don't understand their need to be saved. They don't understand that the wages of sin is death (Romans 6:23)--that sin plummets people into an eternal hell. Consequently they ignore the remedy because they don't even know they have the disease."
-See more: http://www.gty.org/resources/questions/QA69/Why-do-so-many-people-miss-the-real-meaning-of-Christmas