It means there are, and always have been, people who haven’t perfectly slotted into societal expectations
So here's a great idea, let's get rid of the bullshit, sexist, sex role stereotypes and expectations and stop pretending that appearance or dress sense makes the slightest bit of difference to, or alters, a person's sex.
I don't slot perfectly into societal expectations. I don't pretend it means I'm not a woman though. Instead I fight sexist bullshit and that includes the appropriation of my sex by male people who want everyone else to pretend being a woman is nothing more than clothes and a special feeling that they can have too.
It's the very definition of female sex based oppression, that a group of males have simply decided that our very sex class must be redefined without question so they can pretend it includes them.
There is only male or female.
Transwomen are male.
'Woman' is simply the word for an adult human female, like 'hen' is a female chicken and 'mare' is a female horse.
The only people who need 'woman' to mean a set of sexist, sex role stereotypes, are males who wish to insert themselves into a category they don't belong in by divorcing the word woman from any biological meaning of anything solely female.
If 'gender' isn't sex, and 'gender identity' is some unprovable, entirely subjective feeling only a tiny % claim to have, why do we suddenly need to remove sex segregated spaces and female protections, in order to accommodate male people who claim to have a gender identity?
The male sex class commit 98% of all sex offences, regardless of any identity, and is one of the main reasons why we have sex segregated spaces in the first place.
You cannot have a rule that allows 'some' men into women only spaces.
It's all or nothing. Especially as 'trans' is now nothing but someone's say so.
The teacher in the op is simply showing the world the absolute absurdity of gender identity ideology and how ridiculous the laws in some countries are that give a certain group of people permission to behave with impunity and have their 'feelings' placed over and above the safety privacy and dignity of females, and the safeguarding of children.