Wow, this thread is still alive...thanks?
Anyways, I just want to say there are plenty of studies on marijuana, from it's uses, benefits, side-effects, risk, addiction and so forth. Just searching marijuana on my school's database brings up 500K articles, over 30K scholarly peer-reviewed, which should be no surprise since we are already lawfully using it medically. Thus, any personal experiences, incidents and "my bro smokes a half-O a week and he got 95% on his women's study final", are not valid, as weed from an illegal dealer, is not and will not be same as weed from a registered, legal dealer. If marijuana becomes legal, it will be controlled, just like alcohol and any other drugs on the shelves of your local shoppers drug mart.
The groups of people, without point out political groups since it's too vague, that I find are most opposed of marijuana are parents and business owners. The concern of parents is simple, their kid smokes weed, enters a phase of trying out new drugs and shit, then either ends up in jail or go through some Breaking Bad shit. With BOs, they fear the overall productivity will drop, as the side-effects of weed is reduced focus, mellowing out and mad munchies. More call-ins, less focused employees equals no mo money. I don't even want to get started with the religious groups...
Moving on, the issues that I find with Marijuana almost the same as the issues we see with alcohol. Alcohol is legal, regulated and controlled, but what's to stop someone from abusing it and entering a downward spiral to jail? With BOs, I think their worries are exaggerated, as there is nothing stopping you from imposing your own rules. You're the boss and your employees will listen, if they want a paycheque.
Another problem with just about any argument, is that most people are seeing Marijuana from how they were taught to see it, as bad, illegal and the prize of gang A vs gang B. With everyone else, we accept them without even being taught about what they are, because the marketing from TV ads, sports, etc. are already doing that. Molson Canadian ads with dudes having a BBQ, employees on the verge of diarrhea feeling better after taking Pepto, hockey player with itchy balls soothing the pain by pouring Gold Bond down his pants, just to name a few, so a few arguments out there that are being seen as objectively valid, are biased.