The history of it goes back to the same era when the US implemented prohibition. Sweden had a referendum about having prohibition as well, but the prohibitionis

The history of it goes back to the same era when the US implemented prohibition. Sweden had a referendum about having prohibition as well, but the prohibitionists lost by a small margin, so instead of banning alcohol sales, they just kept the pre-existing WW1 rationing of alcohol in place even after the war ended. Eventually the rationing was removed but the government monopoly was kept in place.