Spacey, you must have been dawdling through the intersection. I'm happy to be corrected if I'm wrong, but I believe the amber light gives sufficient time to clear the intersection if you are still facing a green light when you enter it. The idea is to give you time if you are too close to the line to stop.
My car is fitted with that device that changes every light to red as you approach, so I try to always be prepared to stop. I assume it will turn red, but continue in case it doesn't. When it turns amber I stop unless I am only a meter or two from the line. Cars in other lanes may overtake me, but that's the risk they take.
There is always the exception. One night we had a call from a hospital where my wife had been having tests during the day, asking her to come back in straight away.. It was about 9:30 at night and the road was wet. There were no other cars about. As I approached, the lights turned amber. I would have had to brake hard to stop in the remaining distance, and I was afraid I might skid, so I took the risk. About halfway through the intersection the lights turned red and the camera flash went off. I got the fine in the mail saying I was 0.6 seconds in the red light. I appealed explaining the circumstances, but the appeal was dismissed. Them's the breaks, I had to take it on the chin.