"Defend" Christmas???

Apparently Christians all over America are feeling attacked for their beliefs because you and I say "Happy Holidays" to each other and because someone somewhere decided that the Christmas tree shouldn't be so called. Organized Christian groups who apparently have nothing better to do (like, I don't know, rally to help the poor, homeless and starving of the world) are actually putting their energy together to boycott stores like Target for using the phrase "Happy Holidays" and not "Merry Christmas" in their holiday ads.

One such argument is made on the webpage of a fellow classmate of mine, and apparently, if Jesus were walking the earth today, he'd be sending little postcards of protest to the ACLU, rather than trying to fight the injustice and suffering of the world.

I am thoroughly confused, on so many levels, not least the which is the meaning of Christmas. Fortunately for you all, it is finals week, so this will be short. But here are a few questions:

1. Where in the Bible is a christmas tree mentioned??? I may not be a biblical scholar, but I really don't remember that part...
2. When did Christians decide that they were actually happy with (and wanted to be represented by) the horrid gluttony and consumerism of the holiday season?
3. Do I have to say to you "Merry Christmas" starting right after Thanksgiving or can I just reserve it for, oh, I don't know, maybe December 25th?