Capricious violence, racism, and corruption are so endemic to american policing that every cop is either an active participant, or aware of specific instances and complicit in this lawlessness. The internal culture of policing enforces this through peer pressure, hazing, and threats and violence if necessary. Good people can become police but they can't stay police: they ultimately either warp their morals to conform to this system or leave it entirely.

Considering this a problem of individual cop incompetence is naive honestly. This "problem" is so widespread, so universal, that you can't understand the role of police in society without accounting for it. They aren't incompetent and failing at their job: this is their job! Terrorism against the dispossessed is an important part of what they do, and they are doing it.