It's not about the legitimate/medical/supervised usage, it the recreational use that kills. Marijuana (MJ) is used a lot recreationally; if people to use MJ instead of Fentanyl the OD cases would not pile up like they do today.
> Does that mean driving a car should become illegal, and marijuana legalized?
Honestly, yes. Or at least driving a car should require a much more strict licensing process. My daughter got a license during the pandemic and all that was required of her was driving around a parking lot once and then parking parallel. Skills which can be acquired in a couple of hours just prior to the test. Yes there is usually a written test as well, so there is some reason to believe people know what the basic road signs mean, but to let people loose on public roads traveling at 70 mph after a 5 minute driving test is just asking for widespread vehicle collisions.
That's not comparing like for like. For better or worse driving is considered to have huge social utility.
Fent addiction has huge negative utility for everyone - except its manufacturers and their investors.
MJ is probably more or less neutral.
In terms of broad social effects, refined sugar is probably the deadliest of all drugs, but its direct effects - especially in sodas - are much smaller than its indirect contribution to obesity and diabetes. And unlike a dramatic overdose death, it's very slow-acting. So it's barely considered a problem.
Hard line policing is the problem, not MJ/opiates itself.
If you get in as much trouble doing/buying/selling/etc MJ as Fentanyl, you might as well do the latter.
If MJ is legal, many would stick to that.
Same for MJ-to-alcohol: and the alc producers know it, they lobbied fiercly against legal MJ and when it became legal (like in Canada) they were the first to invest heavily in it.