I didn't know this, so I concede, somewhat. But my broader point remains. Availability bias makes the problem seem much much larger than it actually is.
The reality of the availability bias isn't in question, it's whether or not people's belief about police brutality is accurate and if not, why it isn't. Sure, the AB is real. It MAY be a factor in why people think black people are killed in proportionally higher numbers than people of other races, but what's relevant is whether or not it's actually happening.
https://www.factcheck.org/2015/11/trump-retweets-bogus-crime...
Starting with the most obvious point, the Crime Statistics Bureau of San Francisco doesn't exist.