While I agree with the point you're trying to make, that image is pretty useless without some units on those axis and citations for the studies that determined the numbers.
Heroin apparently ranks "almost" a 3 on this graph, the highest shown, but not quite a 3. Why does it fall slightly short? If this is purely comparative then why isn't doesn't the most dangerous drug align with the highest number? And why 3? A scale of 1 to 10 seems like a more common choice for arbitrary scales. And where would something obviously more harmful (like say, draincleaner) fall on that graph? It tells us that Heroin is apparently more harmful than cocaine, but gives us absolutely no indication of how much so. THC ranks as a '1' on this harmful meter. Does that mean heroin is only 3 times as harmful as a substance that nobody has ever overdosed on?
I could construct a similar graph with water, apples, and THC, but it would end up being extraordinarily misleading and just as useless. In fact, the more I think about it, this is probably the worst graphic I've seen in a long time, there are just so many layers to what's wrong with it...
Linking me to the methodology used to create that graphic might be a nice start. At least enough to simply suggest it just wasn't pulled out of somebodies ass...
The point is that it DOESNT MATTER what the scales or methodology was. There is no study or methodology or renumbered axis that will place alcohol to the left and bottom of marijuana. All that matters is that alcohol is above N2O and that heroin is above cocaine and that tobacco is to the right of marijuana etc.
The point I was originally making is that alcohol and tobacco is IN THE MIDDLE of all the illegal drugs in terms of damage and addictiveness and therefore you can't argue that they should be legal or illegal base just on those 2 factors alone.
Here's the study though in case you still want to look at it:
^ Nutt D, King LA, Saulsbury W, Blakemore C (2007). "Development of a rational scale to assess the harm of drugs of potential misuse". Lancet 369 (9566): 1047–53. doi:10.1016/S0140-6736(07)60464-4. PMID 17382831.
