Not quite true. A yellow light is "stop if it is safe to do so", so you might have to justify not stopping, if charged.You should have fought the ticket then - the machine was out of calibration. You'd have won.
You are legally allowed to enter an intersection on a yellow. It's only after the light turns red that crossing the white line will yield you a ticket. Red light cameras are supposed to be calibrated accordingly....apparently the one you experienced...was not.
(15) Every driver approaching a traffic control signal showing a circular amber indication and facing the indication shall stop his or her vehicle if he or she can do so safely, otherwise he or she may proceed with caution. R.S.O. 1990, c. H.8, s. 144 (15)