They just say that because they want to keep more heroin for themselves.

Poverty and trauma makes peoples faces gaunt and haggardly and destroys lives. Heroin addiction is one of many other potential symptoms of poverty and trauma. Plenty of people use opiates and opioids medically and recreationally to no ill effects. The drugs are a comfortable scapegoat for people who care more about maintaining their personal status quo than the ability for other people to survive.

Edit: you can see from the score of this comment how many people still buy into the drug war propaganda.