Thanks for sharing the personal experience, I'm sorry to hear that your son got addicted.
Although there are some harmful effects of marijuana (as they are in alcohol too), there are many benefits of its legalization, including addict social marginalization prevention, as you pointed out.
What concerns me about legalization at the moment, is it is being promoted as cool rather then a way to help addicts.
I think legalization should be accompanied by the anti-smoking campaigns that targeted the tobacco industry. It is amazing the reduction in the number of people who smoke tobacco as a result of those campaigns and it did not require creiminalization.
I totally agree with your concerns - the reason why I used somewhat grim images in this article instead of happy ones, is because I didn't want to make an impression that I'm supporting drugs and prostitution just because that's now cool and mainstream.
Of course, I think that some of the income from new taxes should be used to promote limited and responsible drugs (including tobacco and alcohol) and prostitution usage.