Actually, a "few bent cops" do mean that all police officers are like that to some degree.

Obviously they aren't all going out and committing crime, but by not policing each other, they are colluding with those who do.

Police simply don't face the same consequences for violent crimes that ordinary citizens do, and that is because of the culture of policing that all police are to some degree responsible for.

When was the last time you heard the officers who are 'doing the best they can' calling for jailtime for fellow officers found to have abused their authority?