“Boys will be boys”

I am in my first year of high school. Our PE (Physical Education) teacher has been out, and we have a substitute teacher who’s male. When he instructs us on what to do most of the boys will be roughhousing, as in talking loudly as if he isn’t explaining and throwing balls around. Annoyingly the teacher doesn’t acknowledge this. They then ask him about everything he just explained (the teacher didn’t even question why or reprimand them), and when I told them they should have been listening (I was put in a group where I was the only girl), one just said “Oh? So you were?” (I was) and that guy in particular just really gets to me. Once when we were playing a game and were off (he has a really bad temper) he beckoned to another girl, and when I came over to his little nook he literally just shooed me away. Honestly, I feel boys can get away with not paying attention and being disrespectful. When I got injured from one guy breaking the rules of a sport the teacher just said “Boys will be boys”. When I grow up I’ll try not to let that be an excuse.