I started to post this as a reply in another thread but before posting I decided it was too far off topic so I started this thread.
I would respectfully disagree with the end of that comment - we will tend toward binary. I have evolved in my opinion of non binary people. So much so that I believe if I was in my 20s I may be living as non binary. It doesn't feel comfortable to me at this point in my life, however, a lot of people in a different age group are identifying as NB or gender- non conforming or queer or androgynous etc etc. If I were to put myself on a stereotypical gender spectrum 10 being girly girl and 1 being alpha male I would probably say around a 6 or 7.
But I do believe in a gender spectrum - it's what's in our heads not between our legs. Well in my case it's an orchie :-D but I digress.
I am more comfortable as binary probably because I feel people are more accepting of me being transgender than presenting multiple ways on different days. But I get it. I used to think that everyone identifying as NB was in denial of being full blown transgender and afraid of transitioning. I have grown.
Transitioning was the right thing for me but I have become more accepting and open minded = less judgmental. I think for some people being non binary is their truth.