Conor Friedersdorf nails it: It Is Immoral to Cage Humans for Smoking Marijuana — in The Atlantic
There are times when locking human beings in cages is morally defensible. If, for example, a person commits murder, rape, or assault, transgressing against the rights of others, then forcibly removing him from society is the most just course of action. In contrast, it is immoral to lock people in cages for possessing or ingesting a plant that is smoked by millions every year with no significant harm done, especially when the vast majority of any harm actually done is borne by the smoker.
That there are racial disparities in who is sent to prison on marijuana charges is an added injustice that deserves attention. But if blacks and whites were sent to prison on marijuana charges in equal proportion, jail for marijuana would still be immoral.
America has used marijuana charges to cage people for so long that it seems unremarkable. The time has come to see the status quo for what it is. A draconian punishment for a victimless crime has been institutionalized and normalized, so much so that even proponents of the policy are blind to its consequences. [...]
I submit that a more urgent problem is Americans who shy away from talk about the dubious moral status of marijuana prohibition. It is, at its core, an exercise in using people as means to an end. The end is maintaining a stigma against marijuana use. And the means is locking humans in cages with dangerous people.
One day, we will look back at that tradeoff in moral horror.