I’m going to have to disagree with you on this one, not because “transgender” isn’t an adjective, but rather because following the verb for “to be” with an adjective is nothing new and is really part of accepted English grammar.
You even used it towards the beginning of your article, although you used the [to be] + [not] + [adjective] which is really nothing more than [to be] + [adjective] anyway. Here it is: “I would like to believe that most people are simply not aware…”
The word “aware” is an adjective. You could have said “I would like to believe that most people are unaware…”
My issue with the term “transgender” is entirely different. Gender is a culturally defined role, or a form of eidos, as I describe in “How Many Genders are There Anyway?” Describing something as transgender does not even make any sense unless we attach it to a gender norm.
For instance, a woman going around in a suit would be transgender w.r.t. 1800s gender norms. It works for cisgender as well. A man wearing a wig would be cisgender w.r.t. 1700s gender norms.
