As a society in general, do you agree that unjust laws, false positives in enforcement, prison slavery, and endemic rampant abuse of authority, are things that exist?
As a society in general, do you think those are a legitimate price to pay "to keep serious transgressors in prisons"?
As a society in general, do you think serious transgressors more often get locked up for life, or more often get a slap on the wrist and a quiet promotion to more serious transgressors?
As a society in general, how do you know - falsifiably! - that prisons are even effective for their stated purpose?
Just like prisons perpetuate crime, excluding sociopaths and their behavior from what is thinkable as human only permits us to ignore them. And to contrive our own excuses for their sub-criminal abusive behaviors - which is the primary way in which they blend in and remain beyond reproach. You are their enabler. Go figure out how to stop being that.