And therein lies the rub. Do you believe that our society would allow people to live with the consequences of their decisions to use drugs and risk destroying their lives and the lives of others? I don't. Show me a proposal that says, "Drugs will be legal, but the government will not be there to rescue you from your mistakes," and I might sign up. Otherwise, it is just me picking up another liability for the behavior of another.
Substitute “alcohol” for “drugs”.
Prohibition is worse than the alternative.
So, you are using the welfare state, which is one abuse of government power, to justify another.