Blame patriarchy, not normcore
This is actually the first time I have heard of “normcore.” And that style (or lack thereof) actually describes exactly how I prefer to dress myself: Function, not fashion. T-shirts, jeans or cargo pants, running shoes, baseball cap, and my trusty denim jacket are my mainstays. My aim is to be pretty much invisible on the street.
But unlike you, I’m a transmasculine person who does prefer to be called Sir (if one must use such an honorific), and unfortunately still gets Ma’am’d and Miss’d quite a bit, over two years into my hormonal transition. I’m actually agender, but since no one could know that unless I tell them, I’m content with being put into the Man box by strangers. I’m told that living in San Francisco affects how people gender me; if I lived in a less progressive area, I might be mistaken for a woman less frequently.
In my opinion, we have patriarchy to thank for this kind of style being considered “unisex,” while putting on a skirt or dress automatically genders a person as feminine. This makes it difficult for people of all genders to express themselves authentically without incorrect assumptions being made. Check out the “What I Wanted To Wear” tag in Gender 2.0 for insights on this from other non-binary folks.
In any case, gender expression is not gender identity. You can wear “men’s” clothes and still be a woman, and the reverse is true as well. Clothing has no gender.