I mean fuck the police and I don't care to defend them but the article literally states they don't know the context. I don't doubt the police will do arbitrary shit, but in this case the narrative is based on nothing, which just makes it random fearmongering.
All the video shows someone being arrested and a bunch of people shouting, we don't actually hear anything as to why he's being arrested.
I've walked that exact street a thousand times, people are carrying and doing weird shit every day, I would be surprised if he's actually being arrested for carrying the bat.