It is really an extension of the "Don't talk to cops" rule[1].
I wish I lived in a world where I trusted the police.
I wish I lived in a world where I trusted the police.
People say this about the police frequently, but seemingly just as frequently forget the tail end of the saying!
This confuses me because it is used in defense of the police. With the full expression in mind, the saying perfectly describes the situation we are in (in America) today. We should be very concerned about the "bad apples", due to the strength of police unions, friendships with DA's, the "Thin Blue Line" etc.