Given that 32% of US adults say they own a gun, I think this is honestly a pretty flimsy excuse. Someone having a gun on their person is not justification on its own for the police to shoot them. And the police statistics don't even tell us whether the gun was even drawn, let alone aimed at the officer.

Take a read of the stories of death from your own source. After you read down far enough, you'll see a few cases where the individual aimed a gun at an officer....and dozens that sound like gunning down someone who was not at all a threat to the life of the officer. People with toy guns. People running away from the police. And this is the accounts written by the police. Imagine if we could read their side of the story! What a shame....they're dead so we'll never know.

If you want to know how dirty the American carceral system actually is, my recommendations would be either Matt Tiabi's The Divide or Johann Hari's Chasing the Scream. If you listen to either one on audiobook, I should warn you, they're filled to the brim with horrifying things no human being should hear without context, so listen to them somewhere private.