Black being “emo”

Why is it that every single fucking black thing is labeled emo?? Like my school bag is black and I was getting it from the lockers after pe and this kid fucking says ‘emo bag’ like over n over again. I was so fucking confused and pissed off so I complained bout it when that kid was round saying something like ‘why does everyone think everything black is emo?’ And that never happened again thankfully. But can anyone explain why everyone’s so fucking stupid, I still get called emo occasionally when I have my head down and am listening to music, all I wear is a fucking navy jumper and black pants, How is that shit emo?! It’s weird asf too cuz when I DO dress emo I don’t get yelled at?!?!?!? It’s all so confusing. >:((((