Why the difference - is it just because these topics are less important than politics?

That's a really interesting question.

The Aumann analysis works well for politics. It works well for some theological questions, too: it's a handy explanation for why schismatic branches of a religion often become mutually antagonistic, for example. It isn't quite a complete description of antagonism when conformity with dogma is a fundamental value, but it's easy to augment Aumann with that.

When it comes to cultural disagreements, though -- arts, music, sports teams -- there's a tacit understanding that people's priors are different. Appreciating that sort of thing isn't just about the immediate experience; it can vary depending on who you're trying to impress, and also on immutable products of upbringing and convenience. And people accept this. No one expects a resident of Oregon to be a Green Bay Packers fan, unless the Packers have been having a particularly good year -- and even that comes with a status penalty associated with the expectation of future defection.