I think we all know the real reasons behind the 'War on Drugs'
It's because the vast majority of 'illegal' drugs are, in fact, natural substances that only need to be refined to be used. The drugs you actually buy from your friendly neighborhood chemist, or prescribed by your happy-go-lucky GP are all manufactured using decades of safely tested chemical compounds, mixed in with some of those aforementioned plants.
Of course, those in the pharmaceutical industry know much more than we do about safe medicines and doses, and have all been vigorously tested and trialed for even longer to ensure yours and my safety.
Of course, all these wonderful drugs are checked and approved by those who know more about drugs than anyone else could possibly know - the FDA and other similar. They ensure that we all take only what they know is perfectly fine and will definitely help us - because they said so.
I'm sure the Shamans of the world, and witchdoctors of centuries past would have loved to have been under the happy blanket of Governments and FDA's, and they would have had no problem being told that the stuff they are using is actually dangerous and you will suffer. Even while the opiates and suchlike they are happily smoking is easing they headaches and other aches and pains. Smiling happily though a slight haze of joy after chewing a shroom, they are blissfully unaware of the dangers of using such substances, that have not been deemed fit-for-use by the powers that be.
It's because these banned substances are... well.. homegrown and therefore bypass the ability of governments and FDA's to make money from them because well, if you can just grow it in your back garden, why would you need well trained lab staff and FDA's in the first place?
It has, is, and forever will be, about money. The good of humankind is secondary.