This is not the point of prison. Whites and blacks, for example, use drugs and sell drugs at the same rates. Yet blacks are incarcerated at a much higher rate relative to their representation in the general population.
Throughout the entire criminal justice process, from arrest to prosecution / plea bargaining to sentencing, blacks are discriminated against and receive much harsher treatment than whites.
More accurate would be, 'people who we perceive to be more dangerous'.
The number of federal and state non-violent drug offenders have increased by 750% and 1100% respectively since 1980. Do you really think that these people are so dangerous?
On top of this, a good portion of felony convictions are erroneous, and recidivism rates are near 67%, meaning our prisons are actively creating criminals.
Regardless, I was asking the question to try and inspire thought about what prison should be. I should have been more clear.