Its harm relative to other drugs misses the point imo.
All drugs are bad, and ideally they wouldn’t exist. It’s the idea that society can prevent people taking drugs which is flawed. All we can do is reduce the harm, and all drugs are less harmful if they are managed within a sensible legal framework which accepts that people will take them and doesn’t penalise them for doing so.
Should we discourage drugs use.
Absolutely, but through education.
Just no.
As has been proven by the entire pharmaceutical industry with their millions of different "drugs" (you might know them as medications) that when taken appropriately, actually help rather than cause harm as you suggest.
The entire premise your following argument is based on, is utterly flawed.