Because we have out-of-control drug problems in our country which present policy completely fails to address.
Repeal tjhe Misuse of Drugs Act 1971. Introduced under American pressure, it is the most disastrous legislation of modern times and has created a huge, uncontrolled and constantly expanding criminal market in all forms of harmful drugs.
Make the Department of Health the lead department on drug policy. We might then get some hope of a realistic harm-reduction policy rather than the ever-more-futile and ever-more-expensive attempts at interdiction.