Absolutely a criminal justice issue. Its an economic issue ("unemployable" people gravitate towards black market labor roles). Its a health care issue (street drugs often stand in for prescription medication, particularly pain relievers and psyche meds). Its a color-line issue (drug use becomes an ethnic stereotype which is used as an excuse to segregate).

All these tail effects make explicit prohibition more of a problem than a solution. Tackling the associated problems - health care needs, jobs program, desegregation - goes a long way towards reducing the incentives to consume (and therefore distribute) harmful substances.

No one is admitting defeat, they are just telling you to stop focusing in on the symptoms and start focusing in the problem. You want to address drug misuse problems in western society? Start by addressing the problems that actually highly correlated with it. Help for unhoused persons. Better mental health systems. Those two things alone could curb a huge majority of drug misuse. If you take care of the symptoms then the problem will be mostly solved without need for any criminalization, be it criminalizing supply or demand. For the rest of people I think more funding of rehabilitation and drug education (and no, just telling people to abstain from drugs is not good education, just like abstinence is not good sex education).