It's also worth noting that both Christmas and Easter were pagan holidays long, long before Christianity showed up.
We even still use the old Norse word
Jul or "Yule" as a synonym for Christmas.
Jul was their winter solstice festival.
That still doesn't answer though why atheists celebrate it because even given all that you've said . . . .
Mrs. Fraggle and I celebrate St. Patrick's Day even though we're not Irish. We celebrate Cinco de Mayo even though we're not Mexican. We celebrate Lunar New Year even though we're not Chinese, Vietnamese, or any of those cultures. So why would we have to be Christians to celebrate
their holidays?
Does anybody really need an excuse to party, if the party's already happening? I sure don't!
. . . . it's still universally understood that it is celebrated in honor of Jesus's birth.
And how long have you been a professional sociologist, which would give you the qualifications to lecture us on just exactly how "universal" this "understanding" is, my dear little Science Child? If you grew up in a community of Bead-Clickers, then of course you've been brainwashed into believing that the whole human race celebrates exactly the way you do. Well guess what? It's not true. I went to several Christmas parties last season, and there was
absolutely no mention of Jesus at any of them! No religious imagery at all. Only secular carols.
It's a Christmas-Chanukah-Kwanzaa-Solstice party.
But even when I was a little boy and nobody had ever heard of the Solstice, Kwanzaa hadn't been invented yet, and there were no Jews within ten miles to tell us about Chanukah, my second-generation atheist parents still celebrated Christmas with a vengeance. We had a big tree, fabulous decorations, lots of cool presents, my mother made wonderful pastries, and I even had an electric train. She had tree ornaments that her (atheist) parents brought over from the old country, those really nice glass ones.
I was conscious of celebrating Christmas when I was five years old, and I never even heard of religion, gods or Jesus until I was seven. In the first grade we learned to sing Christmas carols (no "multiculturalism" in those days) and those were the first songs I ever learned to sing--even though I obviously had absolutely no idea what most of the words meant. I still love Christmas carols because of that and I often sing in Christmas choirs.
Look at it this way: We all celebrate Halloween, right? How many people have the faintest idea what they're celebrating? The eve of All Saints' Day? What the heck is that? Why do we dress up like dead people and ghosts and witches? This is a religious holiday too, but its roots are so far in the past that today virtually nobody knows what it's supposed to be about.
It's just an excuse to have a damn big party!
Oh oh oh, I mentioned Cinco de Mayo but didn't go into it. Quick, all you tequila-swilling Americans, tell me why we celebrate Cinco de Mayo? Because it's Mexican Independence Day, right? WRONG! It's the date of a fairly important victory in the Mexican war of independence, but in Mexico
nobody celebrates it. Just the people in the state of Puebla, where the battle occurred. They think we are out of our minds for celebrating a holiday we don't understand that isn't even celebrated in the country it's from. It's just an excuse to have a damn big party!
Well, so is Christmas. Go off to your church service if you enjoy it. But the rest of us are just going to have a damn big party. At least we have some vague idea what Christmas is about, unlike Cinco de Mayo!
Santa Claus and the Easter Bunny.
About ten years ago I read a piece by a sociologist who said that in modern America, Santa Claus and the Easter Bunny are the two most prominent symbols of Christianity.
Easter, unless one has kids, is an excuse to buy good chocolate at half price on the Tuesday following. Similar with Valentines, Back To School, Halloween, and Christmas. Each candy company has a format to suit each holiday and packages it's wares in shapes and wrapping to suit the theme and colors of the season.
Mrs. Fraggle is a chocolatiere so Easter is a special time for us. She makes Easter eggs with dark Belgian chocolate coating and her own fillings, like margarita or Midori.
But Easter is also special because we used to run one of the world's largest teddy bear collectors' clubs and I was the Bunny Specialist. I have a really cool collection of stuffed bunnies and Easter is the one time of year when I can move some of the teddy bears aside and put them all over the house.
Frankly, in our house it's called Bunny Day as often as it's called "Easter."
Christmas Day and Easter Sunday are the only days of the year that our grocery store is closed.
A lot of Jewish people regard Christmas as a Chinese holiday, because the only restaurants that are open (besides the Jewish ones) are Chinese.