The line here is a little different. I could point a camera out my window and record every license plate that drives by my house, and that would be allowed because its recording public activities, and the data I collect would be private—its mine from my camera.
The question here is if a public/government agency pays a private company to setup cameras in public, for the benefit of the public, then should that data collected by those cameras not also be public?
The courts seem to agree that it should be public, and I fail to see why it shouldn't be. Maybe I should read the opposition briefs on it.