Whereas alcohol makes it better?
A popular if illegal recreational drug that revs up schizophrenia is harmful by any reasonable measure.
Beat that straw man. Who ever said it was harmless?
Obviously, we differ in the value we place on modern societies in mostly permitting alcohol use but banning marijuana. Dismissing that as simple majority opinion gives inadequate credit to the experience and considered judgement of mankind.
Much of mankind has had little experience with marijuana; it was criminalized in this country after generations of legality, amid a wave of demagogery about "crazy Mexicans" and white-woman seducing Negro jazz musicians.
(2) A serious argument for marijuana legalization ought to demonstrate that the harms of marijuana use will not be amplified by its legalization. That seems implausible though.
(3) I have never smoked marijuana, but, like most people these days, I have seen enough of its ill effects to incline me to oppose legalization. Demagoguery and racial stereotypes have nothing to do with it.