I am catholic and it's not that I don't think people should celebrate Christmas, but I do get annoyed when people, for example, my neices and nephews, celebrate it but don't seem to have recognise AT ALL that it's a celebration of the birth of Christ, IYSWIM.
I agree with whoever said about it being all about presents etc now.
I don't not agree with the presents and the lights, but I do like to make a point of doing odd things to remind people around me (family and friends) what we are actually meant to be celebrating, i.e. My DDs have a nativity scene advent calender (each day they add another character to the scene) and I send religious cards, and I make a point of telling my DH's family that I won't be there for Chrismtas dinner until 1pm as I will be taking the DCs to mass on Christmas morning etc etc.
What annoys me is my DH's family all had their kids christened but never take them to church, not even at Christmas.
I just don't think it would do kids (or anyone) any harm to spend one hour of Christmas Day at church.