I've always preferred to wear my hair a little long, when I was in elementary school the other kids called me transphobic slurs several times. To be clear, I am cis, but it still hurt seven year old TheLepidopterists's feelings.
I'm sorry that happened to you 
It's of course a bit different for me, but I also really hated being made to feel ashamed for anything I might do that could be considered "girly" at all. I even made a funny post about this topic recently. There is a scene in I Saw the TV Glow where the evil dad says something like "Isn't that a show for girls?" and it cut through me pretty hard having heard it so many times and having that fear/shame ingrained into me. But yeah, policing gender norms is pretty evil, including when it's done to cis men, and we should all push back against it whenever and wherever it appears.