Not the producer of the soft-drug is factually responsible, the user is. One glass of alcohol e.g. is even considered healthy. One cup of coffee or a coke is not really causing any damage. A piece of chocolate is nothing but an innocent pleasure of fine taste. The legal measures are not sufficient to attain to the control wanted.
Legal measures can be in the service of the material interest of parties involved.
The security of the people is heartened by penalizing driving a car under influence or prohibiting the use of alcohol on the the work-floor. In order to do our work we have to see the reality as it is. That we agree about. In private situations though, the legal matter is finished. The legal settlement is there as a civil public defense against the human weakness of all kinds of drug-escapism for the state of illusion.