I understand your frustration, I am so sorry for your friend. That is entirely unfair and all too common.
As a mother and full time caregiver of an adult son who has schizophrenia and had a history of drug abuse. I would just like to add that before I knew my son was schizophrenic I knew nothing of schizophrenia (sadly a large part of the population also does not know anything or very little about any mental illness) -
So before I finally got him diagnosed I too thought my son’s entire problem was the drug abuse, albeit the worse kind of symptoms I ever saw, still I had no frame of reference to know it could be anything else. I made him go to rehab on several occasions and even the drug counselors there did not pick up on the duality of his affliction.
It took an accidental ibuprofen overdose to get the right diagnosis when the paramedics reported hearing him say repeatedly “The voices made me do it” Up until then he had not said anything about voices to anyone, even me. His diagnosis was officially “Disorganized Schizophrenia” which one key symptom of that besides disorganized thought processes is poverty of speech and speaking in what can only be referred to as a “word salad” where the sentence structure is completely out of order.
My point is even if the person with schizophrenia does no drugs at all, the average layman’s frame of reference is very limited in the knowledge of mental illness, I wish that was not the case. Most people will think odd behaviors are likely due to drugs. That is infuriating and dangerous especially when police or involved.
As for smoking cigarettes, I may have misunderstood your post and if I did I am sorry- but it seemed you said that most schizophrenics are not inclined to smoke cigarettes and actually the opposite is true. All of my sons previous and his current doctors have spoke of the inclination patients with schizophrenia toward smoking and studies have been done it’s prevalence. https://www.ncbi.nlm.nih.gov/pubmed/19794359
Again I am so sorry for your friend and I appreciate you sharing that story, it really sheds light on how under-educated much of society is on mental illness. I would hope that can change in the future.