Sadly, these sorts of contracts or policies are ordinary and expected in private, conservative Christian schools in the United States. A bit of a tempest in a teapot erupted when it turned out Vice President Pence's wife worked at a school that prohibited enrollment by LGBTQ students, or by students with LGBTQ people in their families. I did a story about it, and noticed that language in the student handbook was just as insulting as in this case.
Pence's reaction, by the way, was anger that people were not respecting "Christian education."
I'm sorry if we are exporting this norm to Australia.