Weed harms a LOT of kids. Where I lived in the 80s and 90s you could go to the park and find a bag behind a tree if you were "lucky".
For a lot of kids there, it contributed to them starting to ditch many days of school starting in 6th or 7th grade and ending up with many of them dropping out by 10th or so. It was just a lot easier to spend the day in the hood and smoke or drink then ride the bus an hour (forced bussing) to go to a school where you weren't treated equally-and I'm talking about white/hispanic kids mostly. When I moved there, it was 30% black, and they forced bussing to keep the black ratio right at the different highschools. Within 7-8 years, they had moved the primarily black projects out, but they kept the forced bussing without ever going over the ratios.
WAKE UP GUYS. Sorry. I don't know how that would change if it was legal. It was "practically" legal where I lived if you didn't do something stupid-um...
...and it caused lots of problems for people of all ages. I never smoked though. I was too happy getting drunk all the time. For ME, nothing could have been more dangerous than alcohol, probably. I don't know, weed probably would have been the least physically dangerous drug for me and I would have killed myself on anything else.