The author misses a critical point.  When Canada made cannabis illegal in 1923 there was no scientific evidence that it should be made so -- none ... there was parliamentary debate at all ... no rationale -- with the stroke of a pen, the rights of millions of people were removed.  In 1961 there was little evidence too.  No government anywhere should have the right to take away the rights of its citizens to a plant without damned good reason.  And today -- the bulk of evidence clearly indicates that cannabis is much more benign then many other legal substances  -- and actually has many medical benefits when used intelligently.   In fact, freshly picked cannabis is NOT even psychoactive (many do not know that) and taken as a nutraceutical in smoothies, has huge health benefits for the human 
endocannabinoid system and has put into remission many illnesses such as rheumatoid arthritis and other autoimmune disease.   Look up the work of Dr. William Courtney in the US on U tube!