With the amount of media heroin and other badass drugs have been given these past decades there's no way you can not blame the addicts. Heroin addiction isn't a disease, it's a decission.Yes, there may be social and emotional factors pushing the needle in but it's still a decission.
Let me first say a decision can lead to a disease;
Addiction is a disease, if your addicted to something and become depending to it mentaly and physecly (sorry bad spelling) it has become an disease. Your so depended on it you cant live without it *yeah you can literly die if you dont score your hits (note the medicine you need to take to get of it), so yeah its a mental disease. So its the first step you take, and if you slip away you are screwed.
Besides that i agree with relentless, you shouldnt want to kill drug addict in fact I think you never should wish someone the dead. As far for whos to blame, I think you can blame the whole society, every part to a certain level ofcourse.