2. Even if it were true, nations get to dictate their policies and it is perfectly understandable for them to not want to subsidize drug abuse.
How does legalizing manufacturing of a killer substance stop ODs?
It’s not legalizing it that could potentially help with ODs but regulating it. It’s the difference between injecting a random-assumed-to-be-heroin substance dissolved in tap water on a heated spoon and injecting a known 10mg/mL vial of heroin.
Legal weed in Canada has THC % numbers on it and it makes dosing so much simpler. While the impact of too much THC is nowhere near as bad as opiates, it’s quite nice being able to look at a bag and pretty accurately predict how much to have to get a desired effect.
Edit: same with alcohol. It’s really nice to be able to look at a 355mL can of beer and know that drinking it isn’t going to have the same effect as a 355mL bottle of vodka.
If you need data, look at Portugal.