I agree, just because your light was green don't mean theirs was red, the lights could have been faultly.
I think people are too focused on being right than doing right. Regardless of what colour that light was, I had already crossed and there was a grown woman with a child following me - even if you believed you were on a green light, wouldn't basic decency force you to stop?
However, it was a red light and by the time that idiot was berating the woman, the light was going from red to green.
From the woman and child's perspective, the green man was lit, there was someone crossing in front of them already and the traffic was moving slowly - why wouldn't they start to cross?
The minor concession I could give to the motorists is that the lighting system in that area is awful, I think the whole section needs to be a box junction because frequently motorists find themselves queuing to get out of the junction on a red light then blocking other traffic coming the other way - and often blocking the crossings so pedestrians are unable to cross when they're permitted to.