Subversivism: Sexism that is rooted in the presumption that genders and sexualities that are deemed subversive, radical, or transgressive are inherently superior to those that are more conventional. While this form of sexism is not prevalent in mainstream culture, it does proliferate in queer, feminist and radical circles. - Julia Serano
When I was in highschool, there was a lot of appropriation of bisexuality by girls. In the crowd I hung out with, bisexuality was non-conformist, rebellious, sexy, and punk. That's not to say that every girl who identified at bisexual at that time did so to be radical, and many of my bisexual female friends truly were queer and even ran Spectrum, the GSA at my highschool. I will never accuse any individual girl of not really being bi, because it's not my place to make that decision; nor will I ever say that bisexuality itself is a trend, as many polysexual people continue to be oppressed by monosexism and biphobia. However, I have no doubt that, at that place and time, the trend existed, and that a lot of appropriation did occur. In highschool, although I experienced attraction towards girls and was active in the queer community and the gay-straight alliance, I identified as straight; in many ways, this was because I feared being associated with the bisexual trend and felt that my identity would not be considered valid in such a culture. It wasn't until I got out of that community that I began embracing my queer identity. Recently, I'm beginning to notice many similarities between bisexual identity in my former highschool community and genderqueer identity in my college community today, as well as my own relationship with these identities within the greater social context.
The gender binary hurts us all by instilling gender expectations and promoting sexism, homophobia, and transphobia. Thus, it's completely acceptable for anyone to be frustrated with the binary and to want to smash it (I know I do!), it's completely acceptable to experience anxiety and discomfort with hegemonic gender expectations and scripts, and it's completely acceptable for people to dislike pronouns and labels. In fact, I think all of us should actively pursue a post-gender world. However, appropriating genderqueer identities is not the way to do so. Appropriation is harmful to all people, cis and trans, binary and non-binary.
I've feel like I've covered some sketchy ground, and it's important to once again clarify that no one should ever accuse anyone of not really being genderqueer, bisexual, or any other identity, and a person's pronoun preferences should always be respected. However, I also think it's important for individuals to consider the things they say and why they say. As the article I linked at the beginning explained (and if you haven't read it yet, go do it immediately), appropriation of genderqueer identities is harmful to everyone, and should be avoided. In my community, I've seen first-hand how such appropriation hurts many different people.
Edit: I edited the fourth paragraph because, upon rereading it, I found some of the things I wrote problematic and inconsistent with my actual opinion.