There’s one group of HK/Australian pro-Hong Kong protestors on one side. There’s another group of Mainland students exercising their right to free speech by playing and singing the Chinese national anthem on the other. Was this extremely annoying to the pro-HK protestors? Definitely. Was it offensive to the Australians? Yes. Were the pro-China crowd offended by the signs saying “free Hong Kong”? Yup.
You can see the ensuing minor scuffle ("violent clashes" according to the BBC) between between a tiny handful of students from both sides. I saw exactly one sign being torn down. The vast majority of the students were just standing there peacefully.
The BBC article makes it seem as though the Chinese students strong-armed their way into the crowd and started beating people, which is objectively not the case. This is the narrative of the two pro-HK students who they interviewed. If there is evidence of threats and intimidation, then that evidence should be brought forth and those students should be formally reprimanded at the very least, or expelled/criminally charged/deported at worst if the complaints are proven to be valid.
It’s easy to see why they’d write a story like this though when you see the emotional response elicited even from people here -one can only imagine the effect it'd have on the less educated masses.
[1] https://www.youtube.com/watch?v=9CkH3zqoGWw
edit: Another longer video of the "violent clashes" or "Lennon wall violence in University of Queensland" as described by the Youtube uploader (warning: extremely long and boring video where nothing happens)