And to add more context in an unbiased way. Man in white is white collar worker in central district. I don't know if he's done anything to provoke protesters as pretext.
"journalists" being a general nuisance, possibly trying to provoke him. He says something inaudible, something like "are you a journalist" or "what are you reporting on" or generally along the lines of wtf are you doing.
Journalist starts taunting him, saying he can't understand him. He leaves for the office with people swearing and shouting profanity. He turns around and says "we are all chinese people". More swearing. Some "journalist" closes the door and prevents him from entering. Some masked guy comes out of know where to hit him. Granted he wasn't looking to do serious damage but still a dick move and uncalled for. The guy goes in and someone throws an umbrella at his head. Journalists rush after him after pausing for a while probably because they don't know what else to do.
Glorious isn't it
Do you attend the protests and view these or other activities yourself? Or just reporting on Twitter?
Journalists are helping keep everyone safe, by filming, which discourages most from violence, on both sides. They film both police and protestors.
Just do understand that for many HKers, they believe this is a fight where losing means what happens to Uighurs and Tibetans happens to them.