From the sounds of it, tensions were already running high in the city (and the police felt that they weren’t getting paid enough to deal with it); on top of that the police had incentive to time their strike to happen at the worst possible moment. They were also joined in their protest by other groups inclined towards violence, and had reason to encourage those groups (in order to show that they were needed). The reason all of the quoted incidents happened at once is because a lot of different groups were handed an opportunity on a silver platter by a group who had it in their best interests to see a lot of violence break out.
This is a very different scenario from a controlled, scheduled spindown of a department by the city government.