There is another reason for Cannabis to be 'illegal'; "The Christian Religion".

Long before Anslinger and Dupont started their war on "competition" which Cannabis is for the industries, the Pope(s) already declared war on Cannabis centuries before that.

Reason? Cannabis has been a religious sacrament for "non-Christians" (Read; heathens) since long before the Abrahamic religions were founded and those 'non-Christians' and all their religious habits have been the subject of persecution by "the church" since the inquisition.

In fact, the drugs war is nothing less than an extention of this inquisition, it's not by accident that it is mostly healing entheogens that are religious sacraments for many ancient cultures that have been made "illegal" by the Christian dominated western world (read USA, who dictates the rest)

Just my two cents.