When I was a kid public schools in California could celebrate Christmas as long as they only talked about Santa Claus and not the birth of Jesus. My Jewish classmates were often sad because Santa never brought them presents even though they tried to be good. That wasn't okay.
In many public schools today Christmas and other religious holidays are no longer celebrated, partly because of the Separation of Church and State, and partly to avoid offending people.
But one religious holiday is usually celebrated: Halloween.
What? How can that be a religious holiday? Well, it is in the religion called Wicca. While only a small percentage of people in the US belong to that religion, schools stopped sharing "fairy tales" that refer to a "wicked witch" to avoid offending people who believe in that religion. So, why is Halloween still celebrated in the public schools?
Probably because nobody has complained about it yet. If even one parent complains a religious celebration can't be observed in the California schools.
But if we eliminate all religious celebrations we'll be eliminating a lot of fun.
I wish our public schools would allow kids to learn about various religions and cultures without encouraging them to change or question their own families' beliefs. And the kids should have fun doing that.