Consider application of the law. It's not that people shouldn't be punished, but they aren't punished proportionately. Non-violent offenders are more likely to go to jail if they are a minority.
https://en.m.wikipedia.org/wiki/File:US_Prisoner_Demographics.svg
Equality doesn't mean we all have the same everything, it means we're all treated the same regardless of what we look like or how much money we make. That has never been achieved, but it doesn't mean we shouldn't strive for it.