Why would anyone want marijuana leaglized?

I don't understand who would want it legalized beside major corporations and entrepreneurs like myself who could invest and make it into a major industry just like tobacco. Drug dealers would hate it beside prices would be very low people would be paying nothing. Drug dealers would be outta profit it ain't illegal Anymore so no need to smuggle it. It would be taxed heavily just like smokes so people who gripe about how much a pack of joints would cost. So who wins beside we entrepreneurs and manor companies?