Well, if you're going for purism, you need to get rid of 'God' too by the same rationale. Don't forget Mother's day. It's just a commercial excuse to sell cards that most often takes the place of the day in the Church calender to celebrate motherhood.
By the way, once you take away the Christmas tree and the Easter egg, there still remain the days of the year on which Christ was born and died.
No one is arguing against Jesus being born on one particular day and dying on another.
The question is, which days? You don't actually think Jesus was born on Dec 25 and died on the first Sunday on or after the first full moon after the Spring Equinox( a different day each year), do you?