There are a lot of things that carry potential for social harm. It's the job of a nation's citizens to decide which are socially harmful enough to warrant fines or imprisonment. Ranged weapons certainly carry potential for social harm, but the US has decided they don't cross that threshold as long as they aren't fully automatic or explosive.

I think the social harm of even the most "notorious" drugs, like PCP and methamphetamine, don't cross that threshold, personally. There's a lot of pushback now, but I suspect within a century or so most or all drugs will be decriminalized in the US and many other places, even if mostly for practical rather than philosophical reasons.

Focusing solely on the personal harm arguments can be interesting to think about, too. Can a case be made for legalizing fentanyl, despite it often causing personal harm (death)? I think I lean towards legalizing both buying and selling of it as long as failure to disclosure it's contained in something is illegal; though in practice that might be too hard to enforce, in which case maybe selling should be illegal as long as there's some safe government-sanctioned source of it.

You sound like your knowledge of cannabis is from anti-drug TV commercials. Speak for yourself, cannabis can definitely be a social drug. People are just forced to do it in the privacy of their own homes due to prohibition.