That spinner of tales, Adam Smith, provides the answer:
It is not the multitude of alehouses, to give the most suspicious example, that occasions a general disposition to drunkenness among the common people; but that disposition arising from other causes necessarily gives employment to a multitude of ale-houses (Wealth of Nations, II.v.7).
The same argument is used by gun lobbies: don’t blame it on the guns, for the real problem is the occasional nutter who uses one. More guns, then, since people want them. And more ale-houses, since they meet a certain demand. If someone becomes an alcoholic or murderer as a result, well, that’s their problem.