There is nothing in common between drugs and weapons. Also, the world has not come to an end in Portugal and Uruguay, despite the legalization of drugs. On the other hand, the incidence of violence is the most in those countries where even soft-drugs are illegal.
There is crime and chaos where illegal drugs obtain, not drugs.
Alcohol was once illegal, remember prohibition and all the mafia bosses smuggling liquor?
Crime and guns have nothing to do with drugs, but with them being forbidden.
Their harmful effects are another thing.
Not true! Marijuana carries the same harm as tobacco and easy and everything else. Also causes exactly the same addictive as tobacco. Only after Smoking it affects consciousness, and therefore more harmful.
How we define what is a drug and what isn't is very... weird.
For example, tobacco creates physical addiction, it creates lung, throat and tongue cancer, millions die because of cigarettes and they're legal and widely considered 'normal' and something that isnt' a drug, while marijuana doesn't kill, doesn't create physical addiction and it's considered a drug by some.
Alcohol kills people, it makes you stutter, you can't walk if you drink too much, you sit behind the wheel and you kill someone, millions died because of this, not mentioning other long term effects of overdrinking and it's also considered normal and not a drug.
To sum up my point, 'drugs' are a social construct we shape as we want, narrow minded people think something is bad just because it's illegal avoiding to objectively and critically think about any of those 'drugs', I believe only drugs that cause physical addiction should be forbidden including cigarettes, however this is an impossible dream..
People are dumb and they will continue to poison themselves, so fuck it, it's their own body, let them do whatever the hell they want to do..