Okay, I am going to offer a purely unscientific and off the top of my head hypothesis.
If, that study is the real deal, and that's a big IF--I have long thought PhD and Doctor of Divinity students are running out of topics to do their disserations on and are really REALLY stretching in a lot of cases--the study could reinforce an opinion I have held for awhile now.
That opinion is that if you break it down concept by concept, most Americans will be mostly right of center. And we also know that alcohol relaxes inhibitions and prompts people to say what they really think, and the more drunk they get, the less they are inhibited in saying what they really think. So, those who drink are far more likely to violate their own personal reluctance to express their sociopolitical convictions and because there are more conservatives than liberals, more will express conservative views.
It isn't the alcohol at all that produces the phenomenon. The 'phenomenon' is produced because the conservatives outnumber the liberals. The alcohol just makes them more likely to talk about it.
So there you have it. A perfectly unsvcientific opinion that I don't think anybody can challenge.