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.