The way I see it, drugs legislation is like a ratchet; it's easy to make things illegal, but extremely difficult to downgrade or legalise something that's been made illegal, and thus the only way to have things legalised en masse is to push the ratchet to the point where it's no longer a marginalised minority that's suffering, but a significant portion of society, and thus to provoke a large public backlash against the system of prohibition, and to push it as far and as quickly as possible to maximise the shock value, since people adapt to gradual increments of prohibition.