kicked out for asking about heterophobia

I have two sons at high school in Melbourne. My son's both get good grades, they don't bully anyone and they don't make trouble in class for the teachers. Yesterday my eldest, who's in year 11 came home and told me he got blasted by his teacher and sent out.

The teacher gave out a glossary of terms about 'inclusive language'. The list had 'intersexism, biphobia, transphobia, homophobia, sexism- which were all about hating and fearing those groups. But 'heterosexism' was described as "the belief that everyone is or should be heterosexual, the belief that heterosexuality is 'natural' or 'normal' compared to others".

My son asked why the glossary she'd given the class had every sexual orientation 'phobia' possible except heterophobia- as in fear or hatred towards heterosexuals/heterosexuality. He wasn't rude and he was asking seriously.

My son said she got angry then, and raised her voice, and said it was because heterosexuals aren't hated or feared or excluded. She said that heterophobia 'doesn't exist'. My son asked her if she thought 'heteronormativity is was a bad thing'. She said yes, definitely. My son said, 'but isn't that a heterophobic thing to say?' She just stopped and stared and told him to get out.

Just because heterosexuality is the most common orientation doesn't make it wrong. What is going on with these teachers?