What nonsense is this? Smoking weed next to someone does not lead to addiction. Every place that I am familiar with some form of legalized marijuana consumption says you can't do it just any old place you feel like. So this is also just more BS being spread. You have a very misconstrued understanding of something, and now you're calling it libertarianism.
Passive smoke leads to addiction. It's proven for tobacco. It's the mechanism of the propagation. After some hours of breathing small doses of tobacco smoke, people start to like tobacco smoke and want to smoke it too. Weed or tobacco is not important here.
My parents smoked when I was a child. The memory of being in the car with the windows up makes me anxious even though it's been probably 30 years since I've been in a car with a smoker. I experience acute irritation when exposed to anyone smoking, and much more widespread smoking is one of the major reasons I dislike visiting Europe. I know that I'm far from alone in feeling this way.