In my town, just a couple of weeks ago, a young person died after taking a pill sold to them as ecstacy.
It had been laced with something else and it was that that killed him. Had it been actual MDMA, he would still be alive.
Banning drugs doesn't stop people taking them. Instead, it hands the manufacture and supply of powerful drugs over to criminal gangs. This makes no sense at all.
One of the biggest risks for both casual drug takers and serious addicts is the adulteration of drugs. For heroin addicts, there's a double bind. Most street heroin is adulterated, given how much profit can be made. Sometimes the thing it's mixed with makes it more dangerous for the addict, particularly if injecting it. But with heroin, it's also easy to overdose if you get the dose wrong. So, unexpectedly pure heroin can be a risk too, if the users then take more then they realise.
Drugs like MDMA are relatively safe despite public info campaigns to the contrary, but when people buy a "pill" they can only hope it's pure, and not knowing what you are taking can have potentially lethal consequences.
Drugs like weed have got ever stronger while in criminal hands. Way back when, it used to be normal to smoke homegrown weed, which wasn't that strong. But over the years it's got ever stronger, with "super skunk" now pretty normal and sometimes laced with more dangerous substances.
None of this is improved by drugs being illegal. It makes absolutely no sense to let criminal gangs control the drugs trade. It massively benefits the criminals to keep drugs illegal, while putting both the addicts, and casual users at more risk.
Legalising drugs doesn't mean they'll be sold in corner shops! It does mean that you can start to create sensible policies that treat addiction as a health issue, not a criminal one, and that you remove the control and supply from criminal gangs.