I guess some people like the "I'm about to die from poison" buzz. Truly, I've met a few in my time who went nuts for a bad batch of some drug (X) that only made you feel like you were gonna die. They liked it better.
Me, if I'm going to be talkin to jesus, I'd rather be doing it by choice and not out of pure desperation.
For me, the real case for legal drugs is what happens otherwise. We make the worst people on earth rich and powerful when they are illegal, and in fact they help lobby for stronger drug laws all the time. Prohibition creating organized crime comes to mind as well.
If you look at charts for heroin addiction you'll see a cycle. It becomes large for awhile, then drops off. Why? The theory is that people begin to notice what losers heroin addicts are and are less likely to start themselves. Just like a graph of predator-prey populations.
We know some drugs that really are not anywhere in the same league as heroin for being bad for you, yet are illegal, serve as gateways to the worse ones, simply because once you cross the threshold of illegality - you're there anyway, and the same source can often provide the entire spectrum. Further, after having been told that say, marijuana is "bad" and finding out otherwise, one wonders what other lies one has been told - so it destroys the credibility for people telling you what really is bad.
The main problem I have with all-legal drugs is that there really are some that would be abused very severely - really have no good use, and are really bad.
Many prescription meds would count here - antibiotics are already abused, and there are consequences for non-users when something like MRSA comes about as a result.
Meth - know any meth heads who are still OK? Speed is borrowing life ahead at ruinous interest rates, and meth is the worst deal going on that one - coke at least you get the borrowed life before you have to pay, after all.
A lot of people proved they couldn't handle LSD, to which one builds up tolerance very fast - you really have to wait a long time for a little to do it again, and if after a trip you really want more right off - there's something wrong with you, you're not getting it.
There is something to be said for the case of deterrence by losers, and Darwin eliminating the worst of them - if we didn't have to pay for their health and jail costs.
And it's not just drug cartels that profit from illegal drugs, it's a host of other baddies, among which you'd have to include the DEA, who uses the RICO statute to keep anything they seize - with no recourse even if you're found not guilty later. Talk about a perverse incentive. Agencies that don't depend on congress for their funding are very dangerous to our freedoms - no checks, no balances.
As a guy who used to be a performer in the rock and roll field, sure, I've been exposed to every drug there is - twice if I liked it. I kind of know the score, and it's hard to make blanket statements. There are some people who can become utter alcoholic on just beer - I'd drown! Or pot for that matter, just check out from life.
To me, this seems less of a problem with drugs, than some missing aspect of personality, perhaps responsibility or discipline. These people are just losers - drugs are peripheral to the truth here.
I've been pretty lucky myself - I can be a chippie and take it or leave it. But that is evidently the exception or something close. When I was a teen, I got myself addicted to opiates for awhile. But at some point, I realized my brain was the main, maybe the only thing I had going for me, and so turning myself into a zombie wasn't going to be a good plan. So, I quit. Just like that. I didn't even know what withdrawal was until I took a drug education course in high school later and matched up what they said with how I felt - at that point, I lost all respect for addicts, it really wasn't that bad. Cigarettes are far harder to quit for most people.
Since I grew up when I did, I was exposed to coke long before meth. So, no problems there ever. Someone gave me some meth free (this happens a lot in the rock and roll business) and after trying it - and finding myself more or less unable to stop before I ran out of the free sample - never again. After you're addicted to anything bad once, you learn to be really sensitive to things that want to grab you like that and avoid avoid avoid - at some point it's your freedom to make your own decisions that is as stake, and as someone extremely fiercely independent - well, it's not so hard to take or leave any of that stuff.
I sure would like to see some legalization, enough to put the really bad people out of business, but I can't make myself get behind legal-everything until I see a bit more evidence of that being a really good idea for society as a whole.