"The 'defenders of justice'  would be so much more credible if they occasionally accepted that some are guilty."

Not really. Our country (with its "defenders of justice") is all too ready and willing to find people guilty and throw them in jail. We have 5% of the global population and 21% of the world's prisons (with an 80 billion price tag, yearly.) African Americans are found guilty and jailed 5 times the rate of white people. So it is never "occasionally" that some Americans "are guilty" then brutalized by a prison's habitual cycle of punishment. Lots and lots of Americans are always found guilty. We reduce so many people to the "moral" force of a jail cell.