If you ask 'em, they're all innocent, sure.  Some of them lie.  

But some of them aren't lying when they say they are innocent.   John Thompson hadn't committed the robbery or the murder that, combined, put him on Death Row for fourteen years and in prison for eighteen.  No one was ever held accountable for the withheld evidence that showed he hadn't committed either crime. 

Retired judge and former Williamson County, TX district attorney Ken Anderson served a whopping 10 days in jail for withholding exculpatory evidence that put Michael Morton wrongfully in prison for nearly 25 years.

I don't know what John Hockenjos could have done to avoid being entangled.

Now, I'm sure KC didn't mean that everyone who gets charged with a crime is guilty, but that's certainly the inference I'm drawing from that comment that not committing crimes is a way to avoid entanglement in the criminal justice system.

Given that we have shit for accountability for those who enforce the law, I suspect the number of inmates who aren't lying about being innocent is far, far higher than anyone should find acceptable.

If angels were to govern men, neither external nor internal controls on government would be necessary. In framing a government which is to be administered by men over men, the great difficulty lies in this: you must first enable the government to control the governed; and in the next place oblige it to control itself. - Federalist 51