I'm questioning the fact that these experts (doctors? sociologists?) just scored which drugs they found more dangerous. For starters, effects in the individual and in the community belongs to two completely different areas of expertise.
http://en.wikipedia.org/wiki/David_Nutt: "David J. Nutt is a British psychiatrist and neuropsychopharmacologist specialising in the research of drugs which affect the brain and conditions such as addiction, anxiety and sleep."
Dr. Les King is a well-respected chemist; I'll let you dig up your own references. Dr. Phillips is specialized in decision procedures and policy-making.
Yes, it would make sense to have others look over their conclusions, and yes, at least Nutt and Les King are not sociologists. But both have a long service on various boards on the topic of substance abuse - do you really believe they have no idea what they are talking about, medically or sociologically? Do you really think the Lancet wants to get caught publishing highly controversial rubbish ("link bait")?
And all of this is still just a smokescreen - you don't like their conclusions, fine, but then you'll have to point out that they're actually wrong. Calling their authority into question is disingenuous (especially since they have plenty of authority). Their facts may be incorrect, and there is definitely some subjectivity here (how do weigh damage to self in an individualistic welfare state?), but you'll have to offer better arguments than this.
Appeal to authority is a logical fallacy. The fact that they are well-credentialed does not excuse the fact that the study in question just flat-out isn't science. It's not reproducible without getting the same group back in a room together, it's based on subjective opinion or subjective interpretation of objective data, and it compares legal substances to illegal substances without offering a principled way to control for the effects of that regulation.
Do you really think the Lancet wants to get caught publishing highly controversial rubbish ("link bait")?
Um, The Lancet frequently publishes controversial articles. They published (and later retracted) a paper that claimed a link between vaccines and autism, they put out one of the highest death-toll estimates of the Iraq War, and they've called for a complete ban on tobacco products in the UK, to name a few.
Yes, but the comment I replied to was questioning their credentials, which is at equally invalid - more so, in this case, since they actually do have quite impressive credentials.
With respect to The Lancet: controversy sells, but you still want to have a credible argument.
You are right, though, that this isn't exactly objective and independent of current policy. Then again, it may be hard to get such data...
And you'll need a better argument than "well, that's just their opinion" to sway me.