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’m sorry to hear about your challenges. Religion is not a part of our holiday celebrations. If you go back far enough, Christmas was actually co-opted from paganism in an effort to convert pegans to Christianity. So maybe we call it a Yule parade and everyone can take part?