I would think in the cases of truly rural counties remote from cities of any size, a majority of the voters may, indeed, believe that alcoholic beverages are the tool of the Devil.
But in suburban counties or towns that vote "dry," you may well be right. In the town of Waxhaw, NC, (in my home county, Union, NC's most rapidly growing county, transitioning from the exurbs to the suburbs of Charlotte), liquor by the drink was twice voted down in the past decade, before finally passing a couple of years ago. My take is that the measure was voted down by anti-development people, who didn't want to see more commercial development of any kind in their town.
I don't know that graft was a factor, but economics may well have been -- some probably felt (erroneously, in my opinion) that the values of their homes may have been diminished by increasing development of any kind. These people were not anti-liquor religious fundamentalists; their home bars were stocked, and they didn't mind driving a few extra miles (to southern Charlotte, for example) for a cocktail and dinner.