I know that people have identities like agender and things like that, but would you not say that "NB" has become its own set of social identities in a way that is similar to masc and fem? I've certainly seen something like that in the NBs I've known broadly, and I saw it on places like tumblr (yes, I actually had a tumblr account, I'm not dogwhistling). If you say that's not the case for you and a lot of other NBs you've known, I won't contradict you and you've surely known many more than me, but it seems difficult to really cast off a dimension of social identity in a society that retains it and (as the manifesto asserts) aggressively, malignantly fights to shape you into that social identity, on a level more fundamental than demanding your agab, something that can't be abolished by fiat.
"Yeah, it is difficult, motherfucker"
Fair enough, I'll defer. That said, I still really don't get how a similar claim of casting off gender can be applied to binary trans people (with it always needing to be stated that they are doing no worse than cis people, and probably a bit better).