Continued anti-drug propaganda? Have you never looked up any kind of statistic relating to programs like DARE or anti-drug PSAs? They have absolutely no effect on whether or not kids use drugs. Period. Teenagers such as myself don't take these programs and PSAs seriously because we know we're being lied to. Even the dumbest pot-smoking teenager knows it.
Your assertion that pot smoking can "totally ruin your life when you are about 15" is false; "amotivational syndrome" is a load of shit. Most people who smoke pot in their adolescence try it just a few times; even regular smokers only smoke for perhaps a few years before they lose interest and get on with their lives. Even lifelong smokers are capable of leading successful lives; Carl Sagan was a well-known cannabis user and advocate of its use, and has even said that cannabis has helped inspire his ideas, writings and experiences. As for the link between cannabis and psychosis, it's just that: a link. Not a causal relationship. There's no evidence at all to suggest that cannabis use causes psychotic disorders barring any other confounding factors - such as a genetic predisposition towards psychotic disorders. In most people, psychotic disorders, especially schizophrenia, don't show up until around the age of 19-22. It is very possible that cannabis can trigger psychotic symptoms in people who already have a predisposition, or that people with underlying psychotic disorders are drawn to drug use, or both. Either way, the statistics suggest that you'd have to stop 2,800 heavy male cannabis smokers, or 5,000 heavy female cannabis smokers, to prevent one case of schizophrenia.
In short... cannabis, used knowledgeably and responsibly, isn't dangerous. Anti-drug propaganda is a gigantic waste of tax dollars, and saying that "drugs will continue to be villified" and use viewed as a "contemptible habit" is nothing more than a continuation of that sort of misinformation, and an unfair, baseless discrimination against drug users. Drug use is not inherently irresponsible. Your example with alcoholism is exactly the crux of the issue here. You're blaming the drug (alcohol) for the problem it creates in society, even though you just said that alcohol, when used in reasonable quantities (i.e. when used responsibly) has no significant negative long-term effects. If that's the case, then how can alcohol be causing problems in society? The answer is that it doesn't. Irresponsible people cause problems in society, and drinking alcohol is merely one of many ways in which they act out irresponsibly. Irresponsible people also drive cars and kill people (even without any substances to help); shall we villify the use of cars because they cause such a problem in our society?
The vastly more important thing is to educate people on how to behave responsibly. Yes, it is possible to use cannabis responsibly, just as it is possible to use alcohol responsibly, and the important thing is to show people that it's possible to enjoy these substances - and all the other conveniences of life, like cars - as long as they are careful and responsible about it. That is the kind of drug education we need, not continued villification, which doesn't do anyone any good (after all, we saw how well abstinence-only sex education worked.) I hope this post has opened your eyes to a new perspective on the issue and that you will find at least some validity in what I am saying.