Why did Canada legalize heroin?
Heroin is illegal, no question about it
At some point in their lives, 24% of Canadians have used one or more of the following illegal drugs: cannabis, cocaine. LSD, speed/amphetamines, heroin. More males than females report having used these drugs (30% versus 18%). Cannabis (marijuana/hashish): Cannabis is the most widely used illegal drug in Canada.
Obviously you have little knowledge about Canada, you were mislead or misread something, Canada is going to be in the process of legalizing Marijuana under controlled circumstances like alcohol ie. Age requirement.
Heroin is an absolutely terrible drug/substance and I highly recommend against its use/consumption.
Thank you for reading
As Geoff Smith noted heroin is legal to be perscribed:
Last month, Prime Minister Justin Trudeau's government quietly enacted new rules that will let doctors prescribe pharmaceutical-grade heroin to treatment-resistant addicts, Alan Freeman reported for the Washington Post. The change will, specifically, allow the Crosstown clinic in Vancouver, Canada, to expand a program that lets heroin users go to the clinic - frequently multiple times a day - to safely inject pure heroin.
But otherwise is an illegal drug if not used with a prescription and prescriptions from other countries are not valid in Canada. While pure/pharmaceutical heroin is safe as Geoff Smith noted, the kind you get on the street is addictive and can lead to death.
It didn't legalize it in the way most people think. It made it legal for doctors to prescribe it when other alternative therapies like methadone don't work. It is better to give a heroin addict heroin and gradually lower the dose than to try to get them to go cold turkey.
It has been made available to addicts in controlled environments in order to assist them to kick the habit. It's not legal otherwise.