The heavy taxation and the strict regulation of the market creates a massive cost overhead. Even the lowest quality of legally sellable weed is so expensive that it’s out of reach for poor consumers. The undergroud market may even be able to offer the same quality product for a fraction of the price, for obvious reasons of course.
So many people, especially those with less financial stability, will still choose the underground market over legal options. Also, I’d assume that since the legalization, the pressure by law enforcement has dropped quite a bit, at least for consumers. This would make the underground an even more compelling choice.
"fake or tainted drugs" has always seemed like a bigger problem with different categories of drugs.
Additionally, I'm not convinced it actually reduces gang violence since we still have a thriving black market.
I've seen cannabis with plaster mixed in; glass beads, added ketamine, synthetic fibres; anything cheap to increase the perceived effect and weight. And all of those are safer than legal synthetic 'weed'.
The THC to CBD ratio is completely impossible to control when in prohibition areas. Dealers select for maximum THC to minimize weight to effect ratio, which is the opposite of what you want if you're trying to protect people from any possible psychosis trigger.
People who are self medicating with cannabis in illegal countries have very little control over these factors. If they try to grow their own they can get prosecuted as suppliers and face higher sentences than rapists.
It's not seen as much these days, but was literally a nationwide problem in Ireland for well over a decade.
I presume the "horse tranquilizer" moniker came about as some kind of anti-ketamine propaganda.
And did I mention the theft, in the very short comment you're replying to.The US might have a thriving K market but 90's Ireland did not.