I see arrogant drivers flagrantly running through intersections all the time after the light turns. It is as if they don't have to follow the rules. But if they get hit is it their fault?
The thing to remember is that for opposing traffic, such as while waiting to turn left, lane posession designates right of way. In other words, even if somebody going straight just blatantly runs a red light - and you have a green, you still must yield to oncoming traffic to complete the turn.
Theoretically, that stands because you cannot assume that the oncoming driver has the red without seeing it, nor can you assume that they are actually capable of stopping, thus the greater burden to prevent an accident falls upon the person crossing lanes of traffic. That in no way means that a red light runner is without fault, but merely that they are likely to be assessed with the lesser of the blame.