A big part of the problem is lumping all drugs together in the first place and painting them with the same broad brush.
While it may be true there's no non-self-destructive reason to use some drugs (meth and heroin come to mind), there are plenty of others that many people are able to use responsibly and gain enjoyment, insight, or other benefits from.
MDMA, for example, while widely abused, has shown great promise as a therapeutic tool for treatment of PTSD and can have powerful strengthening effects on relationships. Is it your place to tell someone who stands to benefit greatly and plans to use this drug responsibly that there's no good reason for them to do it? Shouldn't that be up to them?
While it may be true there's no non-self-destructive reason to use some drugs (meth and heroin come to mind), there are plenty of others that many people are able to use responsibly and gain enjoyment, insight, or other benefits from.
MDMA, for example, while widely abused, has shown great promise as a therapeutic tool for treatment of PTSD and can have powerful strengthening effects on relationships. Is it your place to tell someone who stands to benefit greatly and plans to use this drug responsibly that there's no good reason for them to do it? Shouldn't that be up to them?