This is religion.
Seriously, this is what we wacky Christ followers call "catechism."
You can't claim that this gender ideology is neutral. It bucks against history, scientific observation, human psychology, and so much more. To believe there are infinite genders based on one's internal feelings is a matter of faith, and instructing children to use the correct terms and have the correct worldview of that faith is religious teaching.
If you want to teach your kids that this is how the world and morality works, then that is your right, but don't come at me with your make-believe "separation of church and state" that was pulled haphazardly from a Thomas Jefferson letter to tell me that it's okay to fly the rainbow flag above schools, libraries, and embassies, but that reading my Bible on public property is illegal.
The whole "impartial secularism" myth is over. The facade has fallen. The spiritual cold war is now an open one. You call on your gods, and I will call on mine.