So I have a friend who's homeless--I've known him 20+ years, since long before he no longer had a home. Substance abuse? He certainly has a drink from time to time. Mental illness? Occasional bouts of depression, which I've seen get pretty severe on one or two occasions. But I know housed people with far worse substance problems, and with far greater issues with mental illness. You're painting a lot of people with a very broad brush, and neglecting to note that plenty of other people, whose right to vote you seem to have no problem with, have addiction and mental health issues that are as bad or worse than a great many of the homeless. The lack of a street address is the only distinction that is absolute between the housed and the homeless.