[RJL]

I did not understand the “whiskey” part.

I mean why did ‘cowboys’ drink that stuff in the first place?

I once read that while we take clean, safe water out of the faucet for granted, that, of course, wasn't the case in the old West and that beer and whiskey offered some protection in that regard.

I'd guess the alcohol's effect on the cowboys played an even larger part of the attraction though.

[prolifefirst]

In the movie I think the wiskey gave an explanation of how a good father and husband could turn into a spree killer and then turn again into a “dry goods salesman in San Francisco”.

[prolifefirst]

Also,

1) Munny’s first victim was thirsty.

2) It was frequently raining, most especially during the great saloon gunfight.

3) Little Bill couldn’t keep the rain out of his house.

4) As a farmer, Munny’s farm appears to be experiencing a drought.

5) Munny becomes opens a dry goods store in San Fran after the movie’s action.