..when they don't need to be.
I've discussed this a lot with my husband, and we agree - people need to get the stick out of their butts, relax and enjoy the celebrations.
Humans have been gathering together to celebrate the winter solstice for far longer than Christianity has existed. Doing so meets a human need, as a response to the dark and the cold. (Can you imagine the rate of depression if we didn't have social gatherings at this time of year?)
I thought that 'freedom' was a core concept of the USA, yet the 'war on Christmas' types deny our freedom to choose how we celebrate the solstice. If we don't do it their way, we are "Unamerican". (Nevermind that the New England Puritans abhorred Christmas celebrations, and Christmas did not become a national holiday until after the Civil War.
http://en.wikipedia.org/wiki/Christmas_in_Puritan_New_England )
I am an atheist, and I plan to cherish and enjoy the company of family and friends this holiday season. Spending time with people I love is what's important to me.