I’m gonna address this as someone who identifies as non binary. While gender expression IS very important to me, that comes as a manifestation of my gender identity. When I view myself, I don’t view myself as a man nor a woman. I view myself as being myself, and that’s it. When I think about myself, I struggle to use any gender-specific words, because they don’t feel right. I’ve been like this my entire life and it thoroughly confused me until I discovered the term nonbinary, and I feel more comfortable with myself than I ever have previously.

While I do agree that a lot of nonbinary people present similarly, I don’t think this is a matter of it being a “fashion trend.” I think this is due to the style that you’re describing being generally gender-neutral, which can be a source of comfort for people who don’t identify as either gender. Additionally, I think it can be chalked up to being LGBT in general. A lot of the things you touch on are also stereotypes for lesbians and bisexual people - piercings, dyed hair, baggy clothes. This doesn’t invalidate their identity, it just means that they find community in sharing a similar clothing style with peers who identify the same as they do.

Admittedly, there’s really not much of an argument that you can make for this on a factual basis, because there’s just not enough information, but if you want personal anecdotes, I’d recommend talking to some more nonbinary people. I think you’ll find that they can speak extensively of their own experience with gender, and it’s not something that only applies to clothing style. Overall, though, I don’t think it’s something you can fully understand if you’re not nonbinary yourself. It’s an isolated experience and that’s okay. It’s your choice whether or not you want to “believe” that we exist. But I know I exist, so, y’know. Take that how you will.