I recommend reading "In the Realm of Hungry Ghosts" by Dr. Gabor Mate, a physician who worked in Vancouver's DTES. Long story short, most addicts (but in particular the drug addicts we're talking about here), have had traumatic childhoods, often grew up as victims of rape, sexual exploitation, and violence. The fact that they don't seem to care about their own lives is because no one else does. What do you think your self-esteem would be like if everyone treats you like garbage everyday for the past 20 years of your life?

TL;DR - Addiction is not a choice, but a symptom of trauma