Has the guy in this story been convicted of driving under the influence? If not, he's absolutely correct. Putting someone in jail for 9 grams of pot is about as big a waste of jail space as it gets. Then again, I'm under the impression that jail and prison space should be used to keep dangerous people away from society.....not those possessing 9 grams of plant matter.
They didn't put him in jail. They gave him 4 years probation and told him to stay away from drugs.
He chose to continue doing drugs. He violated his part of the agreement.