* historically there's been a lot of "black crime" in the US due to the US police watching black neighbourhoods excessively and being absent elsewhere .. take this all the way back in time to Tulsa and before.
* Subsequently there's been a lot of "black crime" as neighbourhoods have been destroyed by occasional mobs (Tulsa), frequent division by freeways and toxic waste dumps, and the removal of many adult males to the prison system as a result of all the "observed crime" leading to an excess of young males with few prospects.
* Based on that data the modern survellience goes to where all the crime has been created^H observed.
Meanwhile entire areas of US cities get on by considerably less police present and oversight and a great deal less observed crime.