Your first 4 reasons for having this forum dealt with marijuana. This is still widely seen as an illegal drug, which is not permitted to be discussed. And if we're honest, a lot of the discussion in this "potential forum" would talk about marijuana and begin debates on the subject (that shouldn't even be discussed). I vote no.

But what makes the talk of one illegal act allowed over another
I would say its like gambling, but I feel gambling is even worse than smoking pot.
And if anything we see both of them taking opposite directions. We developed a gambling anonymous club, the marijuana in DARE and in Rehab is declining. I don't even think you can go to rehab for smoking pot anymore

And what debates would there be on marijuana? Legalization? That would be a fine topic wouldn't it? It would also fit very nicely in the PARD section with politics.
I dont see a problem with this. Isn't the primary function of any sub topic to allow an audience to have debates and conversations about that specific topic. With the exception of general chat ofc where you can chat about anything (but marijuana )

If we allow people to speak of it, this forum wont become a massive marijuana smoking spamfest. The amount of spam about marijuana in non related subforums would have to either stay the same (or more likely, decrease since there's actually a forum for it now).
I dont see how it can possibly make spam in other sections increase.

And my first four reasons dealt with marijuana because people are far more likely to talk about smoking marijuana then anything else.
I would probably see the topics of conversation going Marijuana >/= Cigars > Cigs, but thats just me. Personally I don't have much to say about cigs then "They are fun to smoke when you are drunk"

Also at what point do we consider this not "Widely seen as an illegal drug"

Just no.

voted yes.. but all these different names weed has.. to me is kinda homo.. I dont give 2 shits what u call it just tell me if its good or not.. and wtf is up with the price?

no need.