It has always been this way. Cocaine, like the drink absinthe, was originally banned at the beginning of the 20th century because of outrage at the "dissolute behaviour" of bohemian people rather than any dispassionate measure of the harm it did.

Marijuana was banned in the 30s largely as a result of one particularly racist FBI agent who saw that it was mainly used by coloured people and so making it illegal had little impact on white people while enabling a moral stance to be taken against the laxity of black people.

All of the Reefer Madness scare tactics of the 50s and 60s was a complete fabrication, as indeed most drug "education" remains today.

Heroin ceased to be a legally available prescription drug in the UK at the beginning of the 70s against the protest of all medical and addiction professionals who were consulted. At the time there were 500 registered addicts in the UK and apparently little illegal trade in the drug. A decade ago there were 500,000 known heroin addicts and that was considered to be a similar number who were using the drug regularly.

So, when exactly has science been involved in the process ? Politicians are accountants, lawyers and public relations people; not only do they know nothing of science, they don't care to know anything of science. Science people are below stairs people, they  do what they're told and are neither seen nor heard. Indeed they are not expected to know of wider events nor are they expected to be able to understand them

As per Stevens views in Remains of the Day;-
Let us establish this quite clearly: a butler's duty is to provide good service. It is not to meddle in the great affairs of the nation. The fact is, such great affairs will always be beyond the understanding of those such as you and I, and those of us who wish to make our mark must realize that we best do so by devoting our attention to providing the best possible service to those great gentlemen in whose hands the destiny of civilization truly lies.

keep to the Fen Causeway