Quite right. It is as simple as that.
You offer advice to a junkie and it falls on deaf ears - thus you've wasted your breath which would have been put to better use elsewhere.
You try to give them an actual hand up and they'll respond by trying to take advantage of your sympathy, kindness, time, and whatever else. You have to actually meet and attempt to help these people to learn first hand that their innate idiocy and self-centredness (albeit the result of their ingested poisons or elsewise) will earn not even genuine thanks.
Their so-called 'suffering' comes not from the anaeshetic qualities of their chosen drugs, but the lack thereof. Basically you can't help someone who isn't prepared to help themselves, and though a rare few have given themselves the time to try, it doesn't mean it's worth the effort for the vast majority.
No drug is so addictive it can't be overcome, but these 'people' are just using drugs as a crutch to avoid taking responsibility for their own actions. The day they decide to do so is the day they can start living - it's not my job to help them. I can only wish they wake up, but that's as far as my involvement will ever go. You can waste you time trying if you want, but their problems are not actually the fault of anyone else (other than the enablers obviously).
There's a Yiddish proverb:
The fool sees happiness in the distance, the wise it grows beneath their feet.
These fools see happiness only in the next vial, bottle, syringe, baggy, whatever, and have chosen to shortcircuit their neurons to diminish both a future and immediate happiness.
Life's a gift, and wasted only on the wasters.
Do I care about the reason for their stupidity? Not in the least! It's entirely their fault.