Humans have always looked for ways to alter their conciousnes. We always will. Societies make decisions on which substances to allow and which to ban. The US has made some pretty bad choices in alcohol and tobacco, one of which causes blackouts and violence, the other as addictive as heroin. Since I choose to use substances that are much less dangerous (pot and shrooms) society vilifies me, go figure.
The costs of our drug policy are staggering, the US has the highest incarceration rate of any society in history (pretty good, we beat Stalin and Pol Pot on this count!). This is a direct result of the mandatory sentencing guidelines that are part of the 'War on Drugs.' Our jails are full of non-violent drug offenders.
I say let folks do whatever they want. Just don't hurt nobody, unless of course they ask you....