As were upppers, downers and other pills. And this practice was stopped -- with popular acclamation -- because of perceived abuses.
The libertarian position was that there was never any abuse and these laws were passed because evil, bogus totalitarian moralist types wanted to control other people.
You'd have to be pretty much blinded by dogma not to believe that there wasn't some kind of problem that needed addressing.
There are a lot of roads to hell built on "good intentions." Alcohol prohibition was one of them. The drug war is another.