The fact that we are discussing a yellow light and not a red one is because the yellow light is a mitigation that significantly reduces the risk of harm from making a wrong (or, shall we say, suboptimal?) decision.
That is to say, that the proportion of drivers having to make the risky decision (i.e. if they were to decide to accelerate through the amber) is significantly reduced... although interestingly I think the principle states that as T(amber) << T(green) the liklihood of indecision for that second case now does increase.
The practice of putting cameras on lights and then reducing the duration of the yellow light is not only an abuse of power but also dangerous.