Results in Portugal show that legalizing the drug trade actually has a more negative effect on end users and society.
https://www.washingtonpost.com/world/2023/07/07/portugal-dru...
https://www.washingtonpost.com/world/2023/07/07/portugal-dru...
Decriminalization (what Portugal did) is not legalization and supporters of either often oppose the other, with detailed reasons why the benefits they see from what they support are not achieved with the other, and why the other is not just worse than their preferred solution, but worse than the pre-existing criminalization.
Particularly, the drug trade is not legalized (or even decriminalized) in Portugal, neither is manufacture (including growing cannabis) for even personal use.