The number was just intended to indicate what a small fraction any individual instance is. Even being additive, and even with undiscovered bad cases, these cases are still not representative samples of US police in general. In other words, as an earlier commenter said, this is partly confirmation bias.
That's not to say these incidents aren't indicative of systemic problems, but that's not the same as saying saying all or most police are like this. What "confirmation bias" means here is that people are looking at the exceptional cases to confirm their opinion of police as a whole, which is objectively a mistake.
That's not to say these incidents aren't indicative of systemic problems, but that's not the same as saying saying all or most police are like this. What "confirmation bias" means here is that people are looking at the exceptional cases to confirm their opinion of police as a whole, which is objectively a mistake.