That applies to every criminal act, so why are we signaling out people addicted to drugs? Plenty of people on Wall Street commit crimes daily, stealing money from innocent people - do we worry about how to preemptively stop them?
The answer, IMHO, is that some have effectively demonized people with drug addictions and people who are unhoused, to legitimize hate and violence in our society (and to get rid of people they don't like). 'I hate/fear unhoused / mentally ill people, so it's ok to choke one to death or lock them away without trial.'
It's not only hurts and oppresses those individuals, but it lays the foundation for the next stages - progressive protestors, and soon mass detention of immigrants. It's either human rights for all or for none.
Why not? Using drugs is illegal.