[Double Naught Spy]

It does not matter where the switch is, everyone (cops and non-cops) are responsible for every round fired from there gun.

While the cop is responsible for every round fired, the position of the switch (as designed) may matter if the design is flawed and hence a portion of the blame may go to the light's manufacturer.

Cops should be held to a higher standard and then this mess would have never happened if
1) he became familiar with his equipment

You know, it isn't enought to be familiar with one's gear, but to be proficient with it.

3) spent some money on a good hand held light

#3 seems to be contradictory to the claim that it does not matter where the switch is. If it doesn't matter where the switch is, being handheld would not have prevented the discharge.

I have always been against gun mounted lights for a few reasons and one is it violates the rule of not pointing a gun at anything you don't intend to destroy.

I take it that you are not familiar with modern weapon lights. Even the smaller handgun lights have enough brightness to light up a large volume of space including nearby people without actually pointing the gun at those people. Hence, use of a weapon mounted light need not violate and safety rules.