> It is up to the society
What is this society that you refer to. Surely it can be the people of the nation, because only 30%-ish of the population votes, so the majority can't be said to be in agreement (I also never recall a nation wide vote on the legality of drugs). Are you referring to politicians' decisions? They are an even smaller part of the overall population and don't even represent the people that they are said to (Money in politics etc). Plus, even if 99% of the entire population were to decide that these drugs are dangerous, why is it then ok to violently stop the 1% from doing something that only harms themselves? If that is just, would it the be ok if 51% of people decided that all soda was dangerous and banned that too? What about cheese burgers, we, as a society, have to stop obesity right? What about cars, which kill more people than drugs ever will?
The idea of the morality of democracy is just another version of the might makes right argument.