People really don't want to believe that "just make it legal" actually works for some reason. There's primary and secondary industry in organized crime and cutting off the primary starves the secondary.

A drug policy that makes it so that nobody who does party drugs has contact with a dealer breaks the entire supply chain because there's no outside money coming in.

"just make it legal" has unintended consequences. The cartels, faced with the loss of income from illegally selling now-legal weed didn't starve. they didn't go "oh, hey, I guess we should stop being criminals". No, they pivoted to heroin which turned into dealing fentanyl with disastrous results for the US. We'll keep losing the war on drugs until we start fighting it with community assistance programs and jobs and houses and doctors and therapists.