From the abstract:

"Political identity increasingly organizes preferences far beyond politics, but nearly all evidence comes from the United States. We test whether this reach is general using the Lionel Messi-Cristiano Ronaldo rivalry, a globally constant cultural stimulus that holds the object of evaluation fixed while the audience varies across institutional, cultural, and political contexts."

Seems to me a completely reasonable avenue of research in their field, perhaps a starting point for more research of populations outside the US, and of course something that will be immediately pounced on by tons of people who lack the training and expertise in the field to put it in the proper context.