The same people who were pushing for the police to wear body cams are going to be the same people who will be pushing to have them removed.
The upside to a police body cam is that it might catch an overzealous cop in the commission of a crime against someone under arrest; at this point, that looks to be about a one in a thousand shot.
The downside to a police body cam is that it is recording the worst behavior of a subject under arrest; the internet makes it permanent. The person might be intoxicated, under the influence of drugs, in a fit of rage, or simply stupid.
The belief was always that there would be repeated instances of police misconduct captured, so much so that the outlandish behavior of any group or groups would pale in comparison to the misconduct of the police that would be caught on camera. But if the police misconduct isn't taking place (or isn't being captured on camera), then the camera ends up doing more harm to a cause than good.
At which point it has to be removed.