snip
Nah, re: 3, decriminalize most every recreational drug less dangerous than alcohol or tobacco (or whatever other legal recreational drug you can rustle up, I guess), or criminalize alcohol and tobacco, is a fairly common position, at the absolute least for rhetorical usage.
... mostly 'cause it's blatant hypocrisy to criminalize things less dangerous than something we consider legal, or refuse to make illegal things that are, often enough significantly, more dangerous than things we classify as illegal, unless you're trying to make some kind of argument outside the harm factors involved*. Makes no gorram sense for weed that's bloody close to harmless on an interpersonal level to be illegal and mere possession and use able to net you decades behind bars when you can buy goddamn alcohol that's competitive with non-suicide firearm deaths just on the roads at the corner store.
Anyway, re: 2, counterpoint tobacco, by and large. The anti-lungkiller campaign has been doing a pretty damn good job of breaking tobacco usage's back in the US, and so far as I've noticed criminal production and distribution, especially organized, hasn't seen much of an expansion. Prohibition was a really,
really shitty attempt at curtailing something's usage, heh. Though from what I've half-heartedly noticed recently-ish, it still apparently managed to crack the stateside drinking culture pretty hard... which was pretty damn needed at the time.
It's still decent reason to be leery about making use of a particular substance illegal, though. Just also happens to be one of the stronger supporting points for legalization, too -- legal domestic weed farming would tear giant chunks out of a whole mess of criminal organizations, as the perennial example.
So far as 1 goes... if not being as harmful as something legal isn't sufficient reason to let something be legal, what is? It's not like something being illegal means it
should be illegal, unfortunately. No small amount of things that can put you in a jail cell for incredibly stupid, poorly thought out, often enough incredibly unjust, reasons.
Something being less harmful than a legal substance might not be a necessary or sufficient reason on its
own to make the substance legal, but it's really quite a strong supporting point. "This stuff does less damage to our society than stuff we say is okay" is a pretty solid reason not to throw people in jail over it, basically. Particularly if the jail time is going to cause more damage than the substance use itself, which is really,
really likely.
*
uh, which you can, but those arguments tend to rapidly turn racist as all fuck or still fall in the favor of legalization... which should surprise no one paying attention considering shitting on blacks and/or poor people is exactly what got the US much of its current drug law