The exoteric explanation seems incompetent because it's veiled in racism and xenophobia to protect and promote corporate and national interests. You can see this just in the terminology used in the laws, like using the term "Marihuana" to invoke anti-Mexican sentiment for heavily taxing the use of hemp fibers in 1937 https://en.wikipedia.org/wiki/Marihuana_Tax_Act_of_1937

Luckily for us DuPont introduced a wonderful petroleum-based "man-made organic textile fiber" (Nylon) in 1938, featuring it heavily in the 1939 New York World's Fair and 1939 Golden Gate International Exposition: https://en.wikipedia.org/wiki/Nylon#Early_marketing_strategi...