There is always a backstory to these sorts of things. I would venture to say the guy had been warned previously for running red lights and let off. He repeated the offence, and the cops just gave him extra rope to hang himself with.
It's not unusual for multiple offences to come from one interaction with a cop. A car may be followed for having a malfunctioning taillight, and the driver may commit several other moving offences before being pulled over -- failing to give way, failing to indicate, running a redlight.
It's funny, though, most people way overestimate their driving ability and awareness of the laws, and a cop following just about anyone would have the opportunity within two minutes to pull them over for an infringement.
We rode bikes in Paris last week. It was organised mayhem in some locations -- the Bastille and Concorde -- but when it came to stopping at red lights, our hosts (on bikes) were right on it. And we saw several bicycle riders being written tickets by the police.
We aren't immune from the law.