Well a lot of people are in denial about being nb or don't want to identify that way. Shame, but absolutely their choice.
I gave my son the 'not necessarily' speech when he came out. I said there were many ways of being a woman and told him how I felt. He replied: sounds like you're non-binary.
I disagreed (while accepting him, because not abusive parent who lives through her child, demands gratitude and refuses to learn new stuff) and carried on.
But over several years, I have come (quite reluctantly) to terms with being nb. I remembered the stress and bewilderment I felt during puberty, and how I'd always felt I wasn't either male or female.
When I was younger, my family assumed I was gay (because stereotyping) and would call me a tomboy - such a hideous put-down of a word, always meaning 'not good enough to be either'.
I've been a feminist since early childhood as a result, furious at how differently girls were treated and the limits put on my freedom. Taught the boy (in fact all my boys) about feminism and respect too.
I know that one day I'll fully accept myself and live as nb, but for the moment it's fine. I thought I'd be unhappy using 'them/they' pronouns, but my eldest goes out with someone nb and I have no issue with remembering to use t⁸hem. So I'll see.
It's so hard to explain but switching from 'Ms' to 'Mx' on many online sites gave me a feeling of profound peace. I know now that accepting myself, fully, is something I will need to do in the future.
Anyway, trans people are just trans. Some are nb masc or femme, others have their own words. Trans people don't owe the world an explanation for being trans - the world owes them acceptance of difference.
Being trans, nb and (for example) nb masc are under the same umbrella for a reason. My son is nb masc but calls himself trans. Many, many other trans men are not nb.
Reading nb and trans people's own words is the way to go, if you want to understand them.
One last thing: just because some people on here feel gender neutral but reject the idea of nb/trans, does not mean nb/trans people don't exist, are wrong or need more information.
Coming out is a long, incredibly difficult process and living openly as trans/nb is actively dangerous. No one would be trans/nb unless it meant everything to them, and profoundly healed them - enabling them to get on with their lives. Trans/nb isn't a lifestyle, it's who someone is.