That argument is dangerous to you and the people you serve.
First, in most states, Joe the Stoner does not go to the pen; he goes to drug rehab or diversion (or he goes home because hardly anybody prosecutes stoners anymore). And everyone advancing this argument should know that to be the case: After all, they are the ones who established alternative drug sentencing in the first place.
The "nonviolent" offenders populating our prisons are not college students caught with dime bags. They are dangerous people who fall into two classes: those who actually committed nonviolent offenses and were convicted of those offenses or those who plea-bargained down from other offenses-likely violent offenses-and were convicted of a nonviolent offense.
"Nonviolent" offenders sent to penitentiaries are not nice people. They could have committed any of the following crimes and still be classified "nonviolent": burglary, breaking and entering, grand theft auto, identity theft, drug trafficking, and the list goes on and on.
And remember, these are just the crimes that got them convicted. It's not hard to imagine that the guy busted for drug trafficking was maybe carrying an illegal concealed weapon at the same time he was collared for slinging rock cocaine and maybe there's strong evidence that he used that gun to throw a few rounds at a rival. Facing an assault with a deadly weapon charge, our drug trafficker is advised by his public defender to cop a plea to selling rock cocaine. Presto! He is now a nonviolent offender.