I think that's being way too charitable.
In a world where people are incarcerated on a scale unprecedented in all of human history, and where prosecutorial success is measured by number of scalps taken, the assumption that this is plain malice designed to let the state rob a few more individuals of their freedom makes much more sense than it all being just a big pile of incompetence and misunderstandings.
This is only true, because prior to these times, people were killed instead. Or beaten to within an inch of their lives. Local "justice", lynching, mob action, used to be far, far more common.
And of course, many people used to be worked to death. Or sold into slavery. Or die from horrid conditions in jail. Or forced into the foreign legion.
While I agree that something may be wrong in the US, there are many regions in the world where the above still happens.