The most disturbing thing about this incident is that no one even tried to help her and a group of girls egged him on and filmed the entire attack. 
Schools were rough back in the day, but there were rules about males attacking girls. A male who hit a girl used to be ridiculed as a coward.

https://media.spinster.xyz/f5ae757f961ac563dbd8057545423a64b9cf9e28fcc22b4d2243498007941dc8.png