The harm to the people connected to the user, if you remove monetary aspects, is mostly grief about their loved one's condition. Not physical harm (usually).

That was basically what I was going for in my reply, but it seems the person I was replying to was just looking for a straw man to attack. Thanks for reiterating.

I don't know what to think in regard to addiction as an illness vs a series of choices. There's so much we don't know about our brains and our genes, and someday we may find that addiction is more attributable to biochemistry than to making choices. (Also, I'm a determinist, so I don't believe "free will" can really exist. But I'm also a pragmatist, so I recognize that it's useful for a society to operate under the assumption that people have agency and therefore can be held responsible for their actions.)