How dare they interfere with our revenue!

The D.C. police chief has denounced an iPhone app as a "cowardly device." These devices alert drivers to potential speed cameras and red light cameras. Of course, when people get the alert, they slow down, become extra vigilant, etc. In other words, they do exactly what these revenue cameras are sold as doing. Why would the police chief be so upset that people are adjusting their behavior in the manner that the revenue cameras are supposed to encourage? Could it be that the cameras really aren't about safety but are about $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ instead?