The study is obviously a flawed one, but it does raise a valid point - but I don't think the findings suggest what people, or the researchers themselves, suggest they do. I would certainly agree that if one isn't as comparatively intelligent, one is more inclined to agree with right-wing opinions - you only need to look at the right-wing popular press, or talk to random people on the street about issues such as immigration, for example, and I think you would notice a trend suggesting that the less intellectual one is, the more likely one is to buy into a right-wing opinion.
I don't think it's at all fair to say this suggests right-wingers are stupid, though. The fact of the matter is most people do not have any great understanding of politics, economics or complex social issues - they only know what they experience and are exposed to through the media. As a rule of thumb, right-wing philosophies and ideas tend to be easier to present in a simplistic fashion than those of the left-wing, and so they are naturally more appealing to persons who aren't accustomed to dealing with complex intellectual challenges. Take the deficit, for example - when arguing between a right-wing austerity driven approach or a left wing Keynesian driven approach, which sounds better?
A person of lass then average intelligence would almost certainly say the austerity driven approach, simply because on paper, it sounds like the most sensible. You cut spending, the deficit goes down. The Keynesian approach is much harder to explain and when simplified, the idea of spending money to reduce the deficit sounds ludicrous to a lot of people. More intellectual individuals can decide between the two approaches on their own academic and economic merits - I'm sure most intelligent, committed right-wingers don't believe in austerity to solve our economic problems just because of a simplistic idea like that; they probably have a solid understanding of economic theory and have chosen the one they believe is more accurate. Any intellectual right-winger, on the other hand, can understand the principles behind the Keynesian approach - they might not think that it works in the real world, but they'll be able to grasp why left-wingers think it should.
It's the same with immigration. Take a group of young, poorly educated, medium to long-term unemployed, working class men. Automatically, we know from our political culture that their natural constituency ought to be the Labour Party - but a good number in that group have very strong right-wing views on immigration (the whole "immigrants coming to our country and stealing our jobs" idea). They come to that opinion based on what they see around them and what the simplistic popular press tells them; they probably haven't give much thought to the complicated economic benefits and the economic consequences of immigration. Again, in contrast, a dedicated and educated right-winger with anti-immigration opinions is more likely to hold them because they've taken the time to familiarise themselves with both sides of the argument, and find the detailed socio-economic evidence and the right-wing explanation for it more convincing.
TL;DR: I suppose what I'm saying is that I think the study is right in suggesting less intellectual people are more inclined to support right-wing views purely due to the simplistic way they can be reached, but that doens't mean left-wingers are any more intelligent, nor does it compromise the integrity of the beliefs and philosophies of educated right-wingers. The study is definitely flawed, but I think it has hit onto an interesting point - more than anything, I think it's just more proof that we need to do more to educate the wider public on the details of politics and basic economic theory.
Those are just my thoughts, anyway.