I do differ here as using drugs within moderation is fine provided soft drugs however the trouble is the youth can normally not define moderation.
I don't see how that's an argument that any (currently illegal) soft drugs should be treated differently to alcohol. In fact I don't see any real evidence-based reason why marijuana, for example, should be treated differently to alcohol.
Legalise it, regulate it and tax it. You'll a) raise tax income, b) save lives by ensuring the marijuana being used is regulated and hence not full of dodgy impurities (that do most of the physical harm) and c) not criminalise a significant number of people. For me, it's simple...