64000 people in the USA DIED OF OPIOID OVERDOSES LAST YEAR ALONE all before the age of 60....
THAT'S what is the major cause
It's an epidemic that is killing Americans prematurely....without healthcare and treatment easily available, it will only get worse.
Perhaps you should voluntarily contribute to a charity that provides healthcare and treatment to junkies. Heck, start your own charity.
Stealing from others, however worthy you think the cause, is still theft and it is still immoral as hell.
Personally, I'd rather see the government decriminalize the consensual activity of an adult, in which case these drugs would not be so unpredictable as to content and potency. Until then, I'll pass on taxing productive citizens in the name of support for drug addicts.