If you raise the issue with the city, then the objection becomes a matter of public record. He wants to be a martyr, and it's going to get him nowhere in terms of getting the cameras removed.
If I don't like how this guy painted his house, am I justified by burning it down? He believes he's acting ethically and he's not affected any type of change by this form of activism.
Don't destroy the cameras. Raise the issue before the city councils and the courts. This type of vigilante logic I could use against the camera smasher too and destroy his own property.