I've done some research on this; quite a lot, in fact.
... Results? Well, actually "non-binary", as applied to people, doesn't have any meaning.
A little more specifically, it has no Bedeuting, as the philosopher Gottlob Frege calls it (whilst possibly having what Frege called "Sinn"). That is, for those unfamiliar with his 1892 paper (the undoubted locus classicus origin of this distinction in the philosophy of language), Über Sinn und Bedeutung, there is nothing to which it refers.
Why is this so? I imagine you asking. It's easy enough. "Non-binary" is taken to refer to human beings who are neither men nor women, neither girls nor boys, neither female nor male. But there are no such people. So the term "non-binary" refers to nothing. (Like, for instance, "married bachelor", "square-circle" or "fractional number whose square is 2".)
There are those who (try to) say things like "non-binary is valid" ... But they don't know what "valid" means either.
Is that any help, @EntirelyMadeofBosoms?