That said, marijuana is certainly less benign than you're making it out to be. I know several people who started using marijuana in high school and became interested in basically nothing else. Anything can become addictive, but biological components that have tolerance factors are especially effective because they cause you to increase your dosage over time.
It's not like doctors in the 60's thought that marijuana was actually lethal, though. The propaganda about marijuana has been divorced from truth basically the whole time, but it's been scheduled anyway.
I find it hard to believe that this is simply a miracle story of the long work of activists finally paying off. There are no free lunches. If we're getting legal marijuana, we're losing something else. So what is that?
Well, what else are we losing?
This doesn't follow at all. The downside to legalization of all recreational drugs is minuscule compared to the societal benefit.
Besides, the current laws are not stopping people from doing it. Most know that weed is something which can be enjoyed recreationaly without risking their health or lifestyle. It doesn't hurt anyone around them, so current law is viewed as arcane and unjust. What benefit are these laws providing to society?