No its not. Your dillusional.
You don’t need to have a gun drawn to be able to shoot a charging animal.
The investigation will happen, and the truth will come out. Hopefully it will conclude a good kill, and not another incident where the cops did something questionable.
Of course you don't, but it does make you more likely to be successful than unsuccessful, especially over short distances.
It's really a time and motion study and one of the main things investigators will look at in comparison to the various statements made by officers and alleged witnesses.
Some witnesses have put the distance well under the 1.5 second/21 foot rule. That a police dog is usually able to cover that distance faster than 1.5 seconds should surprise no one, which makes it likely that the shooter did in fact pull the gun first, that the dog was released after the gun was displayed and not the other way around.