Nowhere in these comments have I see anybody take the position that decriminalization is not enough; drugs need to be legalized and regulated.
I have a close friend whose relative is a heroin addict. According to her, a lot of overdoses are due to almost no "heroin" actually being heroin, rather its fentanyl cut to varying degrees of strength. Not knowing what you're taking, and not knowing how strong it is, can lead to a lot of problems. If people knew what they were getting, and it was legal, you could have "functional addicts" that cause little or no societal harm. My friend's relative was a functional addict on and off for 20 years. She held down a job, paid rent, paid taxes, etc. She decided to get clean only when she had a close brush with death thanks to fentanyl.
Think of it this way: My drug of choice is tequila. When I buy a bottle of 80 proof tequila, I buy it from a state licensed store. I have confidence that its 40% alcohol, and that its safe to drink. It is sold by a reputable company with a brand reputation. What we have today with illegal or "decriminalized" drugs is the equivalent of people dying from drinking bathtub gin during prohibition.