It's interesting how so many people will balk at taking an illegal drug because they "don't want to risk brain damage", and yet will think nothing of driving or riding in a car and risking both brain damage and death nearly every day.
Mountain climbing, rock climbing, skydiving, scuba diving, and even just walking across the street all risk serious bodily injury, brain injury, and death. Yet most people won't freak out if you choose to engage in one of these activities.
But if you dare to swallow a pill every now and then, you're treated as a reckless, immoral madman.
It's because people understand what can go wrong and how it goes wrong in all of the activities you listed above. However I'll wager that many illegal drug users don't know what goes on at all and have no clue what can go wrong. Even when they do, I think it's pretty smart to acknowledge that brain chemistry is far more complicated than car crashes, and it's harder to figure out the unexpected / long term effects of one than the other.
Brain damage from any of the activities I listed above (including car crashes) could manifest itself in any number of ways. And it's impossible to tell ahead of time what the long-term effects of such brain damage will be.
I'm not really sure that knowledge of what can go wrong explains much about the different attitudes society at large has towards drug users vs people who engage in other risky activities (including simply riding in a car).
Most people know that if you ride in a car you could get in to a car accident and you could be maimed or killed or wind up a vegetable. How does knowing these potential effects explain the differing attitudes towards car drivers vs drug users?
That's a pretty weak argument. We know that there are certain situations in those sports that can cause brain damage, like getting hit on the head by a rock and lack of oxygen. We know them fairly well, and the majority of people avoid them successfully.
With rock climbing or driving or scuba diving, it's an "It might happen to you, but if you avoid these extreme situations it won't" situation whereas with taking drugs you can't really avoid pitfalls, other than taking care not to take too large a dose.
With drugs it's likelier to be "you get smaller amounts of damage if you take smaller doses" or plain "we don't know what the fuck this thing does".
I agree that it doesn't explain much about the attitudes. The default attitude should be ambivalent until we know more, not hostile.
"With rock climbing or driving or scuba diving, it's an "It might happen to you, but if you avoid these extreme situations it won't" situation"
Except that there are no such guarantees. It could still happen, and it does happen all the time. These are not risk-free activities, even when performed with all reasonable care. Of course, there are more and less extreme ways to engage in these activities, just as there are more and less extreme ways to use drugs.
You could, for instance, drive really recklessly, speed, or drive drunk. You're exposing yourself to more risk this way. Likewise, you could dive in more dangerous waters, and expose yourself to more risk. There are also known dangerous drug combinations, like mixing opiates and alcohol and going swimming. (In fact, mixing most any drug with alcohol is probably a bad idea, but there are some that are more dangerous than others.) And just as there are safer ways to drive or scuba dive, there are safer ways to use drugs.
Saying "we don't know what the fuck this thing does" is not really true for most drugs. Most drugs do have rather well defined effects. Of course, when you're dealing with black market drugs, the risk is greater that you won't get the drug you're expecting, or that it'll be cut with some other drug you weren't expecting, or that the dose will be different from what you expected, but there are ways to mitigate these risks. And not all illegal drugs need come from the black market. There are legal sources of illegal drugs, paradoxical though it may sound.
The other interesting thing is that not all drugs that are illegal in one place are illegal in all other places (or times, for that matter). And there are plenty of legal and yet quite dangerous drugs (like alcohol and nicotine, not to mention a plethora of prescription and even over-the-counter drugs). So the legality or illegality of a given drug need not have much to do with the its danger. In fact, the scheduling (ie. "illegalization") of some drugs has often driven people to use more dangerous legal drugs.
Mountain climbing, rock climbing, skydiving, scuba diving, and even just walking across the street all risk serious bodily injury, brain injury, and death. Yet most people won't freak out if you choose to engage in one of these activities.
But if you dare to swallow a pill every now and then, you're treated as a reckless, immoral madman.