Guilty until proven ...
... otherwise? No pun intended! I reckon some still don't know how good their life is - that they can't just be locked away. Even for petty crimes - if someone doesn't like how you look or what your political views are .. or just to save their own son. You pick your poison (not literally of course).
Prison dramas - if you've seen a few, you may be privvy to some cliches. But this movie is able to avoid most of them. Maybe the fact that it is based on true stories - on what actually happened (more or less) many years ago. The director, whom you may know from other things, is really on point here. The message is delivered quite powerful.
Even if you do not agree with some of the choices the main character does or takes ... well it does make sense. Not just for the movie, but for the character and his own moral compass and own ... well character! Again no pun intended.
A tough watch, especially when it does get violent, which happens occasionally ... with I assume real images from back in the day in the end credits. Also some events summarized right after the movie ends ...