Many successful, influential people had drug and alcohol problems. Leaders, philosophers, writers, surgeons, entertainers, mothers, fathers, brothers and sisters have been addicts that were never a direct, physical threat to anyone but themselves.
That doesn't distract from the fact that this problem can be solved without resorting to vigilante justice and out right murder. Death shouldn't be the punishment for having a problem.
Here's an idea... those Filipinos over there have such a violent country! They just can't get there act together! I guess Filipinos are prone to violence, and they DO pose a direct, physical threat to everyone in the world! So, go ahead and kill a Filipino if you see one -- you'll just be putting them out of their misery -- and of course we're so benevolent, we offer free rehabilitation (AKA prison) for any Filipino that turns themselves in.