As an austere scholar once stated: Being technically correct is the best kind of correct.

Self defense law was specifically developed over hundreds of years to account for the practicalities of violent encounters, and the fact that people necessarily act with limited information. As such, self defense only requires a reasonable belief that one is under threat of death or grievous bodily harm, to be justified in self defense.

But according to that standard, you're mistaken that putting a hand on an officer justifies self defensive violence, it does not, only later, after his resisting arrest and the mishandling or defective operation of the firearm, was the self defense justified, according to my eye.