People don't brew their own alcohol, either, and do you know why? It's because it's a huge, time-consuming process. To make any significant amount requires a huge infrastructure, and there's basically no way you could do it illegally (and actually, you are allowed to brew your own alcohol in your home in America, but almost nobody does it because it's little payoff for a lot of effort). This is in stark contrast to something called 'weed' that is ridiculously easy to cultivate.
People also ate raw/undercooked meat for thousands of years and chopped each others' hands off for stealing, I suppose that must mean that these are also fantastic ideas which need to be brought back pronto, right???
Well, as I (sort of) promised, here are three peer-reviewed, published, and credible studies on marijuana:
It adversely affects student performance and/or mental acuity.
It's addictive.
It is detrimental to your health.
And I doubt you even skimmed that. The gist of the article was: woman having insomnia/anxiety 10 years after regularly smoking weed, columnist consults three professionals, all of whom say, "Your symptoms probably aren't from pot, but don't smoke it anyway because it is terrible for you." In addition to going against your point completely, as a newspaper column that article isn't terribly credible - it falls somewhere between the studies I just posted and a blog.
Anyway, although I rebutted that source you posted, I have a feeling that, above all else, it indicates that I'm being trolled, so I'm probably not going to reply to you any further. That, plus I've spent way too much time in this thread in the past already.