Too many self-interested people
1. For every scientific survey, another will have a different conclusion and most of us will ignore the ones that are inconvenient, especially if they concern our own habits.
2. My daughter was very, very, very ill. I visited her in one hospital in the North and one in the Sourth of England. I saw rather a lot of patients. I spoke to a lot of staff. My sister-in-law worked with youngsters with various problems and backgrounds from illness to just bad families, in a third area (she had to deal with a couple of suicides where the child went home for the weekend and returned at once to "harmless" cannabis, plus others with less final results). I can assure you that those who have to pick up the fallen do not agree with this "harmless" judgement and will tell you that the combination of cannabis and lager is filling the hospitals. I live in a country (not Holland) where the stuff was tolerated for a while, even being sold in shops and openly smoked on trains. I can say without a doubt that, at least in young people, smoking cannabis does them no favours. Just ask teachers trying to teach them. Even my daughter is strongly against it now.
3. As anyone with serious, practical knowledge (not as a patient) can tell you, the effects are not just loss of memory and motivation (and libido apparently, plus loss of normal dreams); people react differently, as one would expect of drugs playing with your brain chemistry and some do become violent and their judgement about the safety of working or driving under the influence is rather less reliable than that of most drinkers.
4. Since when did the bad effects of, for instance, too much alcohol, smoking or fatty food justify the propagation of another problem? Just because nicotine is freely available (though being more and more restricted) why would you want to further more stuff?
5. Freedom! What would you know? Should I be free to take what I want from whom I want? To lie in a drugged or drunken stupor across bus seats or even on the pavement? Whose freedom? What about my freedom not to smell the stuff when out? Not to have to allow for idiots unaware of their mental state and not caring? I am relishing the spreading freedom of being able to eat in a restaurant or drink in a pub without choking on some nerd's cigarette smoke, brushing his ash off the chair and table and having to air my clothes for hours to get his stink out of them afterwards. Why is some inadequate person's freedom to fill his void with cannabis more important than mine to have clean air and not worry about the pothead in a car? Oh, read some real figures: several years ago it was all ready recognised that "recreational" drugs (i.e. not nedicinally necessary) are involved in a disproportionate number of accidents at work and on the road. And do not go on about responsible smoking or ingestion in your own home, unless you intend to stay there (no children in the house please) for a couple of daysafter your dose: I assume you do know it accumulates and the traces take nearly a month to clear completely from your system.
I am generally all for maximum freedom and personal responsibility. But the abiltiy of drug consumers to fool themselves is not reassuring. I could not care how great you feel on it. Perhaps I get my kicks out of dodging cars on the motorway: hardly a justification or evidence of lack of harm.