I agree with your interpretation of that site's text, but I don't believe that text is an accurate interpretation of California law. It would be a violation to cross the stopping line when the light is steady red unless for a turn on red after stopping when that's not prohibited by a sign at the intersection (as in this intersection) or by a red arrow (not all states prohibit turns on red arrow after stopping). But afaik, there's no prohibition of being over the line when the light turns red. Only for crossing while red, or entering without the exit being clear.
