Addiction does not really happen by choice -- or no one would drink or smoke or eat sugar etc.
Refusing to look at the many factors and complex causality behind addiction is a part of the disastrous, unscientific and inhumane narrative of the war on drugs.
Junkies are the kings of selfish behavior, and they have little to no regard for how their actions affect their loved ones. Lies and the eventual grief of their loss are their legacy.
I have buried enough friends to know this as a fact.
If you look at someone struggling with addiction and all you see is these labels and judgements, how can you see the person? How can you gain a new understanding about something you believe you already know?
I am sorry you've lost close ones and I hear your pain. I imagine you already suspect that it's not as simple as someone being a selfish junkie".
Not all ailments are the same. There's room for human intervention in addiction, both from oneself and their family. We can't always be blaming God for our misery.