1. Maybe, just maybe, this is part of the reason why most colleges boast a four-year graduation rate of 50-60%?I would also like to add that I have spent many years at multiple college campuses, and If smoking marijuana indeed makes people stupid, then there would only be a handful of people graduating each year. Furthermore, I have noticed that the higher ones intelligence level is, the more likely they are to realize the war on drugs is unfounded. I have only met a handful of PHD level trained individuals that wouldn't advocate more sensible drug laws.
Also, there are ways of taxing it. They have found a way to tax all the other chemicals, which by the way have began killing more people than the drugs that aren't allowed in doctor controlled setting. Ie more people OD on the schedule that oxycodone falls into than do on the far more schedule that drugs like heroin and PCP fall into.
What this boils down to is that one cannot get a patent on a naturally occurring chemical, one can get a patent for a synthetic. One can't make much money if they can't prevent direct competition.
2. My research wasn't done on a college campus, but in the real world. Yes, I have come across some very intelligent people who abuse drugs but they are the exception rather than the norm. Drugs users aren't necessarily stupid or of below average intelligence, but they aren't Albert Einstein either. Maybe what you should have said is the more time one spends on a college campus seeking a degree, the more liberal they are apt to become, and thus the more liberal their stance will become regarding the use of illegal drugs.
3. Taxing drugs doesn't prevent people from od'ing on them. All it does is give the government more money to spend to help take care of the people that can't stop at "high" and have to go all out to "wacked out of my f'in brain" and get themselves taken to ICU.
Philosphically, I agree with a lot of what you are saying. I do think we are all responsible for our own actions. For example, I don't think a bar owner should be held responsible for the guy who has a couple of drinks and leaves, but if a bar owner, in the interest of business and profits, serves someone alcohol until they are drunk and then allows them to leave, why shouldn't they be held responsible? Just like the drinker, they had a choice, and could have cut the person off and/or called them a taxi or DD.
The problem with the whole "I can do what I want as long as it doesn't hurt anybody else philosphy" is that invariably someone else always gets hurt, but nobody wants to take the blame for it.