IMHO only reason cannabis is illegal is it's a threat to Pharma Industry, Pharma Lobby, aka organized, legal crime.
Then it's a societal choice between the benefits of easier access to it for medical use (non-OTC drugs are harder to get when you need them) plus lower burden on law enforcement when it does not have to deal with this anymore, and the opportunity cost to society when some people don't use it responsibly and waste their chances. I see positives and negatives for both choices.
(I don't believe other drugs being legal is an argument, alcohol and tobacco wouldn't be legal if discovered today but because they have widespread use it's impossible to forbid them)
Citation needed on that one.
I don't have strong opinions on this, I was mostly a bit triggered by the parent's comment weird theory that "cannabis was only forbidden because of criminal big pharma". (I assumed "only reason" implied that they thought it was a safe drug without side-effects or risks; all (medical/non-medical) drugs have side-effects and risks so not being 100% safe isn't a reason for banning by itself, but that's a factor in the risk/benefit balance).
I think they meant more that the negative effects don't seem that big because most people are ok even with such a large proportion of people already being experienced with it.
> triggered by the parent's comment weird theory that "cannabis was only forbidden because of criminal big pharma".
I don't believe it was either but I'm not sure your counter evidence really works. The science that you alluded to about long term effects all significantly post-dates the ban so couldn't have played a role in it.