Why? Not every story has two sides. Here one group used violence on another that didn't. Unless you have evidence that the pro-HK protesters actually used violence first, that's the only side to the story. The mainland faction being riled up doesn't excuse violence.
Just because it's not a massive riot where the streets run red with blood doesn't mean it's not a worrying instance.
>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.
On the contrary, it objectively is the case, as the first video you yourself linked to shows: it opens with a pro-mainland student in black rushing into the pro-HK crowd and assaulting someone with a crowd screaming and advancing behind him.
It's very strange that you're working so hard to downplay what happened. Not just downplaying, willfully distorting what the videos show.