Rabies is also a health issue, yet that doesn't mean we let rabid people out on the streets to terrorize others. The government is also responsible for the reasonable safety of the public, and psychotic people (regardless of the cause) shouldn't be given free passes to be out in public.

the opiod substitute given to this person's relative made him no longer psychotic

I was responding to the claim that most of the societal harm comes from demonization. No it does not. It comes from the behavior of the addicts.

the behaviour of the addicts is (largely) due to the addiction, therefore anything which impedes the addict from getting treatment (such as demonization) is the main driver of the societal harm which arises due to addiction :)

I say largely because there ARE people who simply will refuse treatment due to other personality issues, or are generally anti-social otherwise.