If you dont feel the same about alcohol you're a hypocrite.
Drug laws, like any other vice law, are primarily designed due to people who cannot handle "too much of a good thing." I myself have been able to use pot on occasion without any addiction or impact on my work or life, same as alcohol (and I love me some alcohol).
Where I digress from drug legalization advocates is the legalization of all drugs. Some to me have too much of a downside for users, i.e. with things like meth and heroin, where the ability to casually use with out acute societal and person side effects is far less than alcohol, pot, nicotine or caffeine. I would also add things like Ecstasy and magic mushrooms to the legalization category.
Any law against a vice must have a tangible, and overwhelming postitive impact on society vs. the cost, both in terms of economics, and when it comes to drug vices, on the cost of the reduction of our freedoms due to the needed zealous policing required to bring it about.