I don't get that argument. How is a red light camera different than surveillance footage that show a murder? It's not a witness, it's evidence.
A red light camera generally can't prove you're the person driving your car - they usually don't have the resolution nor the angle to show the driver.
in your murder example, you would still need to be arrested by a physical person in a police uniform, you would have some interaction with an agent of the state.
when you get a ticket in the mail, who is your accuser? Whose name is on the ticket? what is their badge number? how do i lodge a complaint against this officer? Who is expected to show up in court to prosecute this case?