one should be aware of everyone. no matter in which country such things happen. those who do it and also take it up. Embarrass yourself. also with all the bullying videos from Russia. where several beat a girl. just as hideous. From this point on, it doesn't matter what the person concerned has done. the very large majority of people will always support the affected person. and curse the attacked! as long as they are not rapists, ers, or ers! They recognize the stupidity of these people by this. that they film their crime and that they make it easier for them to arrest.
Those are not underage students....they look like they are in their early 20s. As for the language they are speaking, it's regional, since the Chinese language can vary differently from city to city, with very unique accents. So I could only make sense of certain phrases they used. The curses and swear are obvious but i am certain one of the girls said "you dealt with the wrong man" . Since they are definitely not students, they are probably hookers or prostitutes like @wiksa mentioned.
Now I hear another rumor: These girls are not students, they are prostitutes, the girl been beaten because she walked in wrong territory and stole others guest. So they give her a hard lesson.
The full version is 3:52, the nude girl (15yo) was found dated with another girl‘s boyfriend, so they strip her and beat her and order her to separ legs and slap herself. During this they even give the boy a live show (not included).