This is just stupid.
I’m an atheist. A devout atheist.
This is not “secularism”, it’s stupidity.
As atheists, my family celebrates the traditional secular commercial Christmas. We will also happily attend Chanukah celebrations, Kwanzaa celebrations, winter solstice celebrations, Nicholas Day celebrations, Yule celebrations, Festivus celebrations, or whatever else we are invited to attend. Our beliefs are not so delicate that they could collapse just from being exposed to others joyous celebrations. We love participating in other people’s joy.
This sort if fanatical secularism sucks all of the joy out of the season.
I understand what you’re saying, but Christmas is quite literally the celebration of the birth of Jesus Christ. It very much falls into the “religious” category.
The only thing that it could be besides a Christian holiday is a capitalist holiday. Both of them aren’t great, and should quite frankly be treated as equals if you’re trying to remain neutral.