I’ve seen a fair few industrial accidents including amputations and deaths. I don’t think that the injuries we have each seen are very relevant.
The things that are detected and punished are not necessarily the things that cause harm. Smoking pot a week ago isn’t actually a problem. Being tired from watching Netflix all night is far worse, as are a few other things, including drugs which aren’t readily detected. The imperfect system currently used causes one hell of a lot of harm. There needs to be something, but the current system isn’t right.