You have the police, some are corrupt, some are a bad fit for the job, some are lazy and stupid, and some are run-down and underpaid.
You have prosecutors making their careers on win/loss records and being tough on crime so they can make judge or DA. Ibid for politicians with tough on crime, drugs, etc.
You have the prison system which has become big business, exploiting prisoners, their families, the legal system, and taxpayers. They do nothing to offer a real chance at reform, are dangerous and breed more hardcore criminals and victims.
You have the media which at it's mildest still runs with "if it bleeds it leads", middle of the road "true crime" podcasts and series, and at it's most exploitive preys on scaring the shit out of people (nancy grace is a good example) that 'the bad men are coming for your daughters' and we have to absolutely destroy criminals at all costs.
Then there is the populace who under no circumstances will forgive or trust anyone (background checks, public offender lists, mugshots) who has been convicted of a crime (really in the US these days you don't even need to be convicted, just accused of certain crimes and it is a defacto life sentence).
I am not saying policing shouldn't be reformed but that is one small step in fixing a very large problem but it is a very convenient target to lay all the blame on, and it feels good and just because it is an easy answer that is popular because in the US we are really all culpable.