The difficulty is three-fold, imho. At least with the U.S. system. I cannot speak to the Australian system of justice.

1. We have too many laws on the books rooted in outright systemic discrimination -- the long history of marijuana prosecution because it was predominantly used in the Black community originally is a prime example -- or are just outdated oppression of lower classes, and too many law enforcement personnel who enforce the laws in unequal and discriminatory patterns to benefit those in power.

2. We have far too many attorneys, creating an overly-litigious society that King George III warned us about, and constantly in search of loopholes and obscure technicalities for either prosecution or defense.

3. We have totally given up on any attempts at rehabilitation in our prisons for those convicted of even minor crimes. The prisons largely have been privatized, and they pay minimal pay for guards who are largely unsupervised and see their jobs solely as treating inmates in nearly, and sometimes not even nearly, criminal ways themselves. They have become criminal factories where people are incarcerated for relatively minor infractions, become recruited into criminal gangs out of self-preservation, and come out bigger criminals than they were going in. If they ever were a threat to society to begin with.

It is a complex conundrum that cannot be solved with weighing in on only one side.