How can a society that allows drinking alcohol and caffeine ban a plant you can grow on your window cill? How can a society that will give Ritalin to a child,

How can a society that allows drinking alcohol and caffeine ban a plant you can grow on your window cill? How can a society that will give Ritalin to a child, dogmatically refuse to give a child cannabis based therapy? Why is the state so keen to control cannabis? Is it simply that the state associates it with hippies? Still? In 2017?