It's utterly absurd to compare arrests to fatal shootings, as if the number 12 million somehow makes the killing, manslaughter and murder of suspects ok. Do some of them deserve it, yep, I'm not arguing those, but there are too many that aren't justified and until the last few years when virtually everyone has a camera, most of these would not only have not been reported, but, like in the Walter Scott case we would have been lead to believe that he was shot because he tried to use a taser on the officer, which, of course we know, thanks to the video, is a lie.
Furthermore, how many other cases of police abuse of power, injury and death occur that don't involve a a suspect killed by a gun?
The culture has changed from the early 90's when I went to school to be a police officer and spent almost a year doing ride-a-longs with police and I saw a lot in my time working beside the police. Today police are being more preemptive, they way that carry themselves is to be intimidating. They are in many places being trained to see the people in the areas they patrol as the enemy. Few are trained in negotiation and how to defuse a situations and they often believe that because they are the authority that they can walk into emotionally charged situations and everyone should just do what they say without question. To expect this is to fundamentally misunderstand human nature and guarantee the kinds of results that are played out almost daily.