Earlier quoted context omitted.
I agree that there are more than 400, we know that just by the number of people getting shot. Now, how many are unjustified? That's the important question.
An important question, and a simple answer: all cases of police misconduct and brutality are unjustified.
How do you stop someone pointing a gun at the police officer without brutality?
How do you stop someone attacking a police officer?
How do you stop someone going for their gun?
How do you stop someone going around shooting innocent people?
etc, etc, etc.