Re: Would someone explain
You shouldn't enter the intersection (junction) if you can't exit it before the light turns red. The amber is giving you information that is supposed to stop you from running red lights or slamming on your brakes. You are supposed to use good judgement and the length of the amber should be consistent based on the speed limit. Unfortunately, neither is a given.
More likely the problem here is the automatic red light camera. Most of them, in the US, are owned by private companies with a revenue sharing agreement with the local governments. It has been claimed that they are profit driven, not safety driven. They have been banned in several US states because they violate the state's constitutions.