new religion for state schools

My 12 year old daughter came home from school today with a they/them pronoun badge. She attends a public high school in Melbourne. The badges were being handed out for free at lunchtime. The options were she/her, he/him, she/they, he/they and they/them. She chose she/they as she thought it was the least-worst option, but ended up swapping with a friend as the friend had been unable to get her first choice of badge.

One of the reasons I choose to send my children to public schools is that I wish to avoid religious indoctrination (there are very few independent schools that do not have religious affiliations, and the ones that do are very expensive), but it seems to me that there's a new religion in town and it's being pushed at public schools without an opt-out option. Adolescence is a tumultuous time, and teens are so easily influenced by their peers. I know of entire friendship groups coming out as non-binary or trans in this same school. I am deeply concerned that they are being taught that they can easily change sex well before they are old enough to understand the life-long ramifications of attempting to do so.