If junkies get their fix, it's literally the only thing they care about. It's them not being able to support their habit with a day job what makes them reckless and dangerous.

If junkies receive their fix from medical authorities, along with a treatment helping them to quit, they even have a hope to become in-addicted again.

Of course, arresting or maybe outright killing a junkie would instantly remove any threat to the neighbors. It just requires stopping to see the junkie as a human in need of help and start seeing the junkie as a violent criminal or even non-human. I wonder if such an approach is sort of dangerous for the society's mental health.