Easier to ask if you know who Harry J. Anslinger was and why his ideas are still policy today in most of the world. His idea of "helping" conveniently enriched himself and played well with the bigoted lawmakers at the time. His idea of alcohol prohibition had unintended consequences but surely a repeat with cannabis would show different results...
Drug dealers, smugglers and users are lobbed together with human traffickers and arms dealers today because of this scumbag. Legalize weed already before the criminal overworld takes over and assists bigots keeping things the way they are. Insanely profitable with more money than you can spend with 0 to pay in taxes. People want weed so who are you to stop them? They're only harming themselves like we do with many other substances. Everybody choose for themselves whether they want it or need to try it. It's so widespread you're criminalizing half the population of the world with this hetz. Stigmas die hard.