just look at the picture in the article though.
Here you have a child who defines as "non- binary", both/neither boy or girl.
The picture shows no "girl" accessories or colours. Only "boys" toys- a football and a vehicle.
So to me, that reinforces the idea that you don't like pink, glittery shit and dolls, then you're not a girl.
I hate being defined by my gender, mainly because "girl shit" is seen as inferior, and I hate being told what I can/can't do, how I should feel, and what I should be good at, purely because of my sex. Non-binary would suit me down to the ground, again not because I don't feel female, but because I don't fit the stereotype and won't be defined by it.
My children often confuse people, strangers cannot usually tell whether they're male or female. Not because they identify as non binary, but because they are not the expected female appearance. One has short hair, one won't wear dresses, one hates pink. All like running around being physical. I have overheard near-arguments in the park between strangers who seem to be scared or worried by these weird creatures they can't instantly pigeonhole into girl or boy. They are all under 8.
I really do worry that gender stereotyping and everyday sexism is what is leading us down this road. Twice today- one here, once on FB, I have read "oh boys will be boys".