When I was much younger I was exposed to a variety of different drug users. Everything you said is 100% spot on with anyone that abused drugs.
I've come to learn that there a few different kinds of drug users.
The first are the users who have not yet had to face the reality of drugs or how drugs affect them personally, even if they are suffering consequences from use. The mental gymnastics at play serve to protect and prolong drug use. I see this all the time with white-collar and middle-class users. They may have to take drugs to function, will crash, lose sleep, have mood swings and resultant relationship problems, but it all gets rationalized away because they have a job and aren't homeless yet.
You'll see things like projection, minimization, rationalization, denial, shifting blame and intellectualization used to defend, deflect and justify drug use.
Another type stays rational about drugs, despite how easy it is to let the honeymoon period trick them into believing that there are only positives and no downsides. They don't tend to lean on the psychological defenses mentioned above. They also tend not to abuse drugs chronically or end up dependent.
The final type, if they haven't died, has been kicked in the ass by drug use and was forced to be brutally honest about it. They might still use, but they know they have a problem, or they might be sober.
If you see a person talking about drug use as if there are no downsides, only positives, you are probably witnessing someone who belongs to the first camp.
You shouldn't be lumping all "drugs" together. Of course technically every drug has a downside, for some it's not significant.
Basically food is just a drug too, except by definition.
Addictive drugs are addictive drugs. If you spend enough time around people who abuse substances, you will see the common threads among them when it comes to how they view their use.
You could replace 'drugs' in my post above with 'alcohol', 'excessive exercise' or 'binge eating' and it would still hold true.
Perhaps I am just a type-a person but I would create separate devastation categories for binge eating and smoking methamphetamine.
"for some it's not significant."
where do i sign up?!?
You might like this book -- "The Pleasure Trap"; summarized here: http://web.archive.org/web/20160418155513/http://www.drfuhrm...
Essentially, they explain how the brain "neuroadapts" to high levels of stimulation to where you are just getting normal amounts of pleasure but with all the negative side effects of the food or drugs (e.g. caffeine) and then you have to go through a painful withdrawal period. The book is mainly about healthy eating and also fasting, but the ideas are more broadly applicable.
See also: https://en.wikipedia.org/wiki/Supernormal_Stimuli http://www.paulgraham.com/addiction.html
It's rare but there are also people who successfully manage their drug use minimizing harmful side effects and getting by just fine.
I addressed this group in my OP:
> Another type stays rational about drugs, despite how easy it is to let the honeymoon period trick them into believing that there are only positives and no downsides. They don't tend to lean on the psychological defenses mentioned above. They also tend not to abuse drugs chronically or end up dependent.